The SAT (/ˌɛsˌeɪˈtiː/ ess-ay-TEE) is a standardized test widely used for college admissions in the United States. Since it was debuted by the College Board in 1926, its name and scoring have changed several times; originally called the Scholastic Aptitude Test, it was later called the Scholastic Assessment Test, then the SAT I: Reasoning Test, then the SAT Reasoning Test, and now, simply the SAT.
The SAT is wholly owned, developed, and published by the College Board, a private, non-profit organization in the United States. It is administered on behalf of the College Board by the Educational Testing Service, which until recently developed the SAT as well. The test is intended to assess students' readiness for college. The SAT was originally designed not to be aligned with high school curricula, but several adjustments were made for the version of the SAT introduced in 2016, and College Board president, David Coleman, has said that he also wanted to make the test reflect more closely what students learn in high school with the new Common Core standards.
On March 5, 2014, the College Board announced that a redesigned version of the SAT would be administered for the first time in 2016. The current SAT, introduced in 2016, takes three hours to finish, plus 50 minutes for the SAT with essay, and as of 2017 costs US$45 (US$57 with the optional essay), excluding late fees, with additional processing fees if the SAT is taken outside the United States. Scores on the SAT range from 400 to 1600, combining test results from two 800-point sections: mathematics, and critical reading and writing. Although taking the SAT, or its competitor the ACT, is required for freshman entry to many colleges and universities in the United States many colleges and universities are experimenting with test-optional admission requirements and alternatives to the SAT and ACT. Starting with the 2015–16 school year, the College Board began working with Khan Academy to provide free SAT preparation.
|Type||Paper-based standardized test|
|Developer / administrator||College Board, Educational Testing Service|
|Knowledge / skills tested||Writing, critical reading, mathematics|
|Purpose||Admission to undergraduate programs of universities or colleges|
|Duration||3 hours (without the essay) or 3 hours 50 minutes (with the essay)|
|Score / grade range||Test scored on scale of 200–800, (in 10-point increments), on each of two sections (total 400–1600).|
Essay scored on scale of 2–8, in 1-point increments, on each of three criteria (total 6–24).
|Offered||7 times annually|
|Countries / regions||Worldwide|
|Annual number of test takers||Over 2.1 million high school graduates in the class of 2018|
|Prerequisites / eligibility criteria||No official prerequisite. Intended for high school students. Fluency in English assumed.|
|Fee||US$52.50 to US$101.50, depending on country.|
|Scores / grades used by||Most universities and colleges offering undergraduate programs in the U.S.|
The SAT is typically taken by high school juniors and seniors. The College Board states that the SAT measures literacy, numeracy and writing skills that are needed for academic success in college. They state that the SAT assesses how well the test takers analyze and solve problems—skills they learned in school that they will need in college. However, the test is administered under a tight time limit (speeded) to help produce a range of scores.
The College Board also states that use of the SAT in combination with high school grade point average (GPA) provides a better indicator of success in college than high school grades alone, as measured by college freshman GPA. Various studies conducted over the lifetime of the SAT show a statistically significant increase in correlation of high school grades and college freshman grades when the SAT is factored in. A large independent validity study on the SAT's ability to predict college freshman GPA was performed by the University of California. The results of this study found how well various predictor variables could explain the variance in college freshman GPA. It found that independently high school GPA could explain 15.4% of the variance in college freshman GPA, SAT I (the SAT Math and Verbal sections) could explain 13.3% of the variance in college freshman GPA, and SAT II (also known as the SAT subject tests—in the UC's case specifically Writing, Mathematics IC or IIC, plus a third subject test of the student's choice) could explain 16% of the variance in college freshman GPA. When high school GPA and the SAT I were combined, they explained 20.8% of the variance in college freshman GPA. When high school GPA and the SAT II were combined, they explained 22.2% of the variance in college freshman GPA. When SAT I was added to the combination of high school GPA and SAT II, it added a .1 percentage point increase in explaining the variance in college freshman GPA for a total of 22.3%.
There are substantial differences in funding, curricula, grading, and difficulty among U.S. secondary schools due to U.S. federalism, local control, and the prevalence of private, distance, and home schooled students. SAT (and ACT) scores are intended to supplement the secondary school record and help admission officers put local data—such as course work, grades, and class rank—in a national perspective. However, independent research has shown that high school GPA is better than the SAT at predicting college grades regardless of high school type or quality.
Historically, the SAT was more widely used by students living in coastal states and the ACT was more widely used by students in the Midwest and South; in recent years, however, an increasing number of students on the East and West coasts have been taking the ACT. Since 2007, all four-year colleges and universities in the United States that require a test as part of an application for admission will accept either the SAT or ACT, and over 950 four-year colleges and universities do not require any standardized test scores at all for admission.
The SAT has four sections: Reading, Writing and Language, Math (no calculator), and Math (calculator allowed). The test taker may optionally write an essay which, in that case, is the fifth test section. The total time for the scored portion of the SAT is three hours (or three hours and fifty minutes if the optional essay section is taken). Some test takers who are not taking the essay may also have a fifth section, which is used, at least in part, for the pretesting of questions that may appear on future administrations of the SAT. (These questions are not included in the computation of the SAT score.) Two section scores result from taking the SAT: Evidence-Based Reading and Writing, and Math. Section scores are reported on a scale of 200 to 800, and each section score is a multiple of ten. A total score for the SAT is calculated by adding the two section scores, resulting in total scores that range from 400 to 1600. There is no penalty for guessing on the SAT: scores are based on the number of questions answered correctly. In addition to the two section scores, three "test" scores on a scale of 10 to 40 are reported, one for each of Reading, Writing and Language, and Math. The essay, if taken, is scored separately from the two section scores.
The Reading Test of the SAT is made up of one section with 52 questions and a time limit of 65 minutes. All questions are multiple-choice and based on reading passages. Tables, graphs, and charts may accompany some passages, but no math is required to correctly answer the corresponding questions. There are five passages (up to two of which may be a pair of smaller passages) on the Reading Test and 10-11 questions per passage or passage pair. SAT Reading passages draw from three main fields: history, social studies, and science. Each SAT Reading Test always includes: one passage from U.S. or world literature; one passage from either a U.S. founding document or a related text; one passage about economics, psychology, sociology, or another social science; and, two science passages. Answers to all of the questions are based only on the content stated in or implied by the passage or passage pair.
The Writing and Language Test of the SAT is made up of one section with 44 multiple-choice questions and a time limit of 35 minutes. As with the Reading Test, all questions are based on reading passages which may be accompanied by tables, graphs, and charts. The test taker will be asked to read the passages, find mistakes or weaknesses in writing, and to suggest corrections or improvements. Reading passages on this test range in content from topic arguments to nonfiction narratives in a variety of subjects. The skills being evaluated include: increasing the clarity of argument; improving word choice; improving analysis of topics in social studies and science; changing sentence or word structure to increase organizational quality and impact of writing; and, fixing or improving sentence structure, word usage, and punctuation.
The mathematics portion of the SAT is divided into two sections: Math Test – Calculator and Math Test – No Calculator. In total, the SAT math test is 80 minutes long and includes 58 questions: 45 multiple choice questions and 13 grid-in questions. The multiple choice questions have four possible answers; the grid-in questions are free response and require the test taker to provide an answer.
Several scores are provided to the test taker for the math test. A subscore (on a scale of 1 to 15) is reported for each of three categories of math content: "Heart of Algebra" (linear equations, systems of linear equations, and linear functions), "Problem Solving and Data Analysis" (statistics, modeling, and problem-solving skills), and "Passport to Advanced Math" (non-linear expressions, radicals, exponentials and other topics that form the basis of more advanced math). A test score for the math test is reported on a scale of 10 to 40, and a section score (equal to the test score multiplied by 20) is reported on a scale of 200 to 800. 
All scientific and most graphing calculators, including Computer Algebra System (CAS) calculators, are permitted on the SAT Math – Calculator section only. All four-function calculators are allowed as well; however, these devices are not recommended. All mobile phone and smartphone calculators, calculators with typewriter-like (QWERTY) keyboards, laptops and other portable computers, and calculators capable of accessing the Internet are not permitted.
Research was conducted by the College Board to study the effect of calculator use on SAT I: Reasoning Test math scores. The study found that performance on the math section was associated with the extent of calculator use: those using calculators on about one third to one half of the items averaged higher scores than those using calculators more or less frequently. However, the effect was "more likely to have been the result of able students using calculators differently than less able students rather than calculator use per se." There is some evidence that the frequent use of a calculator in school outside of the testing situation has a positive effect on test performance compared to those who do not use calculators in school.
Most of the questions on the SAT, except for the optional essay and the grid-in math responses, are multiple choice; all multiple-choice questions have four answer choices, one of which is correct. Thirteen of the questions on the math portion of the SAT (about 22% of all the math questions) are not multiple choice. They instead require the test taker to bubble in a number in a four-column grid.
All questions on each section of the SAT are weighted equally. For each correct answer, one raw point is added. No points are deducted for incorrect answers. The final score is derived from the raw score; the precise conversion chart varies between test administrations.
|Section||Average Score||Time (Minutes)||Content|
|Mathematics||531||80||Number and operations; algebra and functions; geometry; statistics, probability, and data analysis|
|Evidence-Based Reading and Writing||536||100||Vocabulary, Critical reading, sentence-level reading, Grammar, usage, and diction.|
The SAT is offered seven times a year in the United States: in August, October, November, December, March, May, and June. For international students SAT is offered four times a year out of USA: in October, December, March and May. The test is typically offered on the first Saturday of the month for the October, November, December, May, and June administrations. The test was taken by 2,136,539 high school graduates in the class of 2018.
Candidates wishing to take the test may register online at the College Board's website or by mail at least three weeks before the test date.
The SAT costs $47.50 ($64.50 with the optional essay), plus additional fees if testing outside the United States) as of 2018. The College Board makes fee waivers available for low income students. Additional fees apply for late registration, standby testing, registration changes, scores by telephone, and extra score reports (beyond the four provided for free).
Students with verifiable disabilities, including physical and learning disabilities, are eligible to take the SAT with accommodations. The standard time increase for students requiring additional time due to learning disabilities or physical handicaps is time + 50%; time + 100% is also offered.
Students receive their online score reports approximately three weeks after test administration (six weeks for mailed, paper scores), with each section graded on a scale of 200–800 and two sub scores for the writing section: the essay score and the multiple choice sub score. In addition to their score, students receive their percentile (the percentage of other test takers with lower scores). The raw score, or the number of points gained from correct answers and lost from incorrect answers is also included. Students may also receive, for an additional fee, the Question and Answer Service, which provides the student's answer, the correct answer to each question, and online resources explaining each question.
The corresponding percentile of each scaled score varies from test to test—for example, in 2003, a scaled score of 800 in both sections of the SAT Reasoning Test corresponded to a percentile of 99.9, while a scaled score of 800 in the SAT Physics Test corresponded to the 94th percentile. The differences in what scores mean with regard to percentiles are due to the content of the exam and the caliber of students choosing to take each exam. Subject Tests are subject to intensive study (often in the form of an AP, which is relatively more difficult), and only those who know they will perform well tend to take these tests, creating a skewed distribution of scores.
|Percentile||Score, 1600 Scale
|Score, 2400 Scale|
|* The percentile of the perfect score was 99.98 on the 2400 scale and 99.93 on the 1600 scale.|
Percentiles for Total Scores (2018)
|Score (2018)||Nationally Representative Sample
||SAT User |
The older SAT (before 1995) had a very high ceiling. In any given year, only seven of the million test-takers scored above 1580. A score above 1580 was equivalent to the 99.9995 percentile.
In 2015 the average score for the Class of 2015 was 1490 out of a maximum 2400. That was down 7 points from the previous class's mark and was the lowest composite score of the past decade.
The College Board and ACT, Inc. conducted a joint study of students who took both the SAT and the ACT between September 2004 (for the ACT) or March 2005 (for the SAT) and June 2006. Tables were provided to concord scores for students taking the SAT after January 2005 and before March 2016. 
In May, 2016, the College Board released concordance tables to concord scores on the SAT used from March 2005 through January 2016 to the SAT used since March 2016, as well as tables to concord scores on the SAT used since March 2016 to the ACT.
Many college entrance exams in the early 1900s were specific to each school and required candidates to travel to the school to take the tests. The College Board, a consortium of colleges in the northeastern United States, was formed in 1900 to establish a nationally administered, uniform set of essay tests based on the curricula of the boarding schools that typically provided graduates to the colleges of the Ivy League and Seven Sisters, among others.
In the same time period, Lewis Terman and others began to promote the use of tests such as Alfred Binet's in American schools. Terman in particular thought that such tests could identify an innate "intelligence quotient" (IQ) in a person. The results of an IQ test could then be used to find an elite group of students who would be given the chance to finish high school and go on to college. By the mid-1920s, the increasing use of IQ tests, such as the Army Alpha test administered to recruits in World War I, led the College Board to commission the development of the SAT. The commission, headed by Carl Brigham, argued that the test predicted success in higher education by identifying candidates primarily on the basis of intellectual promise rather than on specific accomplishment in high school subjects. In 1934, James Conant and Henry Chauncey used the SAT as a means to identify recipients for scholarships to Harvard University. Specifically, Conant wanted to find students, other than those from the traditional northeastern private schools, that could do well at Harvard. The success of the scholarship program and the advent of World War II led to the end of the College Board essay exams and to the SAT being used as the only admissions test for College Board member colleges.
The SAT rose in prominence after World War II due to several factors. Machine-based scoring of multiple-choice tests taken by pencil had made it possible to rapidly process the exams. The G.I. Bill produced an influx of millions of veterans into higher education. The formation of the Educational Testing Service (ETS) also played a significant role in the expansion of the SAT beyond the roughly fifty colleges that made up the College Board at the time. The ETS was formed in 1947 by the College Board, Carnegie Foundation for the Advancement of Teaching, and the American Council on Education, to consolidate respectively the operations of the SAT, the GRE, and the achievement tests developed by Ben Wood for use with Conant's scholarship exams. The new organization was to be philosophically grounded in the concepts of open-minded, scientific research in testing with no doctrine to sell and with an eye toward public service. The ETS was chartered after the death of Brigham, who had opposed the creation of such an entity. Brigham felt that the interests of a consolidated testing agency would be more aligned with sales or marketing than with research into the science of testing. It has been argued that the interest of the ETS in expanding the SAT in order to support its operations aligned with the desire of public college and university faculties to have smaller, diversified, and more academic student bodies as a means to increase research activities. In 1951, about 80,000 SATs were taken; in 1961, about 800,000; and by 1971, about 1.5 million SATs were being taken each year.
A timeline of notable events in the history of the SAT follows.
On June 17, 1901, the first exams of the College Board were administered to 973 students across 67 locations in the United States, and two in Europe. Although those taking the test came from a variety of backgrounds, approximately one third were from New York, New Jersey, or Pennsylvania. The majority of those taking the test were from private schools, academies, or endowed schools. About 60% of those taking the test applied to Columbia University. The test contained sections on English, French, German, Latin, Greek, history, mathematics, chemistry, and physics. The test was not multiple choice, but instead was evaluated based on essay responses as "excellent", "good", "doubtful", "poor" or "very poor".
The first administration of the SAT occurred on June 23, 1926, when it was known as the Scholastic Aptitude Test. This test, prepared by a committee headed by Princeton psychologist Carl Campbell Brigham, had sections of definitions, arithmetic, classification, artificial language, antonyms, number series, analogies, logical inference, and paragraph reading. It was administered to over 8,000 students at over 300 test centers. Men composed 60% of the test-takers. Slightly over a quarter of males and females applied to Yale University and Smith College. The test was paced rather quickly, test-takers being given only a little over 90 minutes to answer 315 questions. The raw score of each participating student was converted to a score scale with a mean of 500 and a standard deviation of 100. This scale was effectively equivalent to a 200 to 800 scale, although students could score more than 800 and less than 200.
In 1928, the number of sections on the SAT was reduced to seven, and the time limit was increased to slightly under two hours. In 1929, the number of sections was again reduced, this time to six. These changes were designed in part to give test-takers more time per question. For these two years, all of the sections tested verbal ability: math was eliminated entirely from the SAT.
In 1930 the SAT was first split into the verbal and math sections, a structure that would continue through 2004. The verbal section of the 1930 test covered a more narrow range of content than its predecessors, examining only antonyms, double definitions (somewhat similar to sentence completions), and paragraph reading. In 1936, analogies were re-added. Between 1936 and 1946, students had between 80 and 115 minutes to answer 250 verbal questions (over a third of which were on antonyms). The mathematics test introduced in 1930 contained 100 free response questions to be answered in 80 minutes, and focused primarily on speed. From 1936 to 1941, like the 1928 and 1929 tests, the mathematics section was eliminated entirely. When the mathematics portion of the test was re-added in 1942, it consisted of multiple choice questions.
Until 1941, the scores on all SATs had been scaled to a mean of 500 with a standard deviation of 100. Although one test-taker could be compared to another for a given test date, comparisons from one year to another could not be made. For example, a score of 500 achieved on an SAT taken in one year could reflect a different ability level than a score of 500 achieved in another year. By 1940, it had become clear that setting the mean SAT score to 500 every year was unfair to those students who happened to take the SAT with a group of higher average ability.
In order to make cross-year score comparisons possible, in April 1941 the SAT verbal section was scaled to a mean of 500, and a standard deviation of 100, and the June 1941 SAT verbal section was equated (linked) to the April 1941 test. All SAT verbal sections after 1941 were equated to previous tests so that the same scores on different SATs would be comparable. Similarly, in June 1942 the SAT math section was equated to the April 1942 math section, which itself was linked to the 1942 SAT verbal section, and all SAT math sections after 1942 would be equated to previous tests. From this point forward, SAT mean scores could change over time, depending on the average ability of the group taking the test compared to the roughly 10,600 students taking the SAT in April 1941. The 1941 and 1942 score scales would remain in use until 1995.  
Paragraph reading was eliminated from the verbal portion of the SAT in 1946, and replaced with reading comprehension, and "double definition" questions were replaced with sentence completions. Between 1946 and 1957, students were given 90 to 100 minutes to complete 107 to 170 verbal questions. Starting in 1958, time limits became more stable, and for 17 years, until 1975, students had 75 minutes to answer 90 questions. In 1959, questions on data sufficiency were introduced to the mathematics section, and then replaced with quantitative comparisons in 1974. In 1974, both verbal and math sections were reduced from 75 minutes to 60 minutes each, with changes in test composition compensating for the decreased time.
From 1926 to 1941, scores on the SAT were scaled to make 500 the mean score on each section. In 1941 and 1942, SAT scores were standardized via test equating, and as a consequence, average verbal and math scores could vary from that time forward. In 1952, mean verbal and math scores were 476 and 494, respectively, and scores were generally stable in the 1950s and early 1960s. However, starting in the mid-1960s and continuing until the early 1980s, SAT scores declined: the average verbal score dropped by about 50 points, and the average math score fell by about 30 points. By the late 1970s, only the upper third of test takers were doing as well as the upper half of those taking the SAT in 1963. From 1961 to 1977, the number of SATs taken per year doubled, suggesting that the decline could be explained by demographic changes in the group of students taking the SAT. Commissioned by the College Board, an independent study of the decline found that most (up to about 75%) of the test decline in the 1960s could be explained by compositional changes in the group of students taking the test; however, only about 25 percent of the 1970s decrease in test scores could similarly be explained. Later analyses suggested that up to 40 percent of the 1970s decline in scores could be explained by demographic changes, leaving unknown at least some of the reasons for the decline.
In early 1994, substantial changes were made to the SAT. Antonyms were removed from the verbal section in order to make rote memorization of vocabulary less useful. Also, the fraction of verbal questions devoted to passage-based reading material was increased from about 30% to about 50%, and the passages were chosen to be more like typical college-level reading material, compared to previous SAT reading passages. The changes for increased emphasis on analytical reading were made in response to a 1990 report issued by a commission established by the College Board. The commission recommended that the SAT should, among other things, "approximate more closely the skills used in college and high school work". A mandatory essay had been considered as well for the new version of the SAT; however, criticism from minority groups as well as a concomitant increase in the cost of the test necessary to grade the essay led the College Board to drop it from the planned changes.
Major changes were also made to the SAT mathematics section at this time, due in part to the influence of suggestions made by the National Council of Teachers of Mathematics. Test-takers were now permitted to use calculators on the math sections of the SAT. Also, for the first time since 1935, the SAT would now include some math questions that were not multiple choice, instead requiring students to supply the answers. Additionally, some of these "student-produced response" questions could have more than one correct answer. The tested mathematics content on the SAT was expanded to include concepts of slope of a line, probability, elementary statistics including median and mode, and problems involving counting.
By the early 1990s, average combined SAT scores were around 900 (typically, 425 on the verbal and 475 on the math). The average scores on the 1994 modification of the SAT I were similar: 428 on the verbal and 482 on the math. SAT scores for admitted applicants to highly selective colleges in the United States were typically much higher. For example, the score ranges of the middle 50% of admitted applicants to Princeton University in 1985 were 600 to 720 (verbal) and 660 to 750 (math). Similarly, median scores on the modified 1994 SAT for freshmen entering Yale University in the fall of 1995 were 670 (verbal) and 720 (math). For the majority of SAT takers, however, verbal and math scores were below 500: In 1992, half of the college-bound seniors taking the SAT were scoring between 340 and 500 on the verbal section and between 380 and 560 on the math section, with corresponding median scores of 420 and 470, respectively.
The drop in SAT verbal scores, in particular, meant that the usefulness of the SAT score scale (200 to 800) had become degraded. At the top end of the verbal scale, significant gaps were occurring between raw scores and uncorrected scaled scores: a perfect raw score no longer corresponded to an 800, and a single omission out of 85 questions could lead to a drop of 30 or 40 points in the scaled score. Corrections to scores above 700 had been necessary to reduce the size of the gaps and to make a perfect raw score result in an 800. At the other end of the scale, about 1.5 percent of test takers would have scored below 200 on the verbal section if that had not been the reported minimum score. Although the math score averages were closer to the center of the scale (500) than the verbal scores, the distribution of math scores was no longer well approximated by a normal distribution. These problems, among others, suggested that the original score scale and its reference group of about 10,000 students taking the SAT in 1941 needed to be replaced.
Beginning with the test administered in April 1995, the SAT score scale was recentered to return the average math and verbal scores close to 500. Although only 25 students had received perfect scores of 1600 in all of 1994, 137 students taking the April test scored a 1600. The new scale used a reference group of about one million seniors in the class of 1990: the scale was designed so that the SAT scores of this cohort would have a mean of 500 and a standard deviation of 110. Because the new scale would not be directly comparable to the old scale, scores awarded on April 1995 and later were officially reported with an "R" (for example, "560R") to reflect the change in scale, a practice that was continued until 2001. Scores awarded before April 1995 may be compared to those on the recentered scale by using official College Board tables. For example, verbal and math scores of 500 received before 1995 correspond to scores of 580 and 520, respectively, on the 1995 scale.
Certain educational organizations viewed the SAT re-centering initiative as an attempt to stave off international embarrassment in regards to continuously declining test scores, even among top students. As evidence, it was presented that the number of pupils who scored above 600 on the verbal portion of the test had fallen from a peak of 112,530 in 1972 to 73,080 in 1993, a 36% backslide, despite the fact that the total number of test-takers had risen by over 500,000. Other authors have argued that the evidence for a decline in student quality is mixed, citing that the reduced use of the SAT by elite colleges has decreased the number of high scorers on that test, that top scorers on the ACT have shown little change in the same period, and that the proportion of 17-year-olds scoring at the highest performance level on the NAEP long-term trend assessment has been roughly stable for decades.
Since 1993, using a policy referred to as "Score Choice", students taking the SAT-II subject exams were able to choose whether or not to report the resulting scores to a college to which the student was applying. In October 2002, the College Board dropped the Score Choice option for SAT-II exams, matching the score policy for the traditional SAT tests that required students to release all scores to colleges. The College Board said that, under the old score policy, many students who waited to release scores would forget to do so and miss admissions deadlines. It was also suggested that the old policy of allowing students the option of which scores to report favored students who could afford to retake the tests.
In 2005, the test was changed again, largely in response to criticism by the University of California system. In order to have the SAT more closely reflect high school curricula, certain types of questions were eliminated, including analogies from the verbal section and quantitative comparison items from the math section. A new writing section, with an essay, based on the former SAT II Writing Subject Test, was added, in part to increase the chances of closing the opening gap between the highest and midrange scores. Other factors included the desire to test the writing ability of each student; hence the essay. The essay section added an additional maximum 800 points to the score, which increased the new maximum score to 2400. The "New SAT" was first offered on March 12, 2005, after the last administration of the "old" SAT in January 2005. The mathematics section was expanded to cover three years of high school mathematics. To emphasize the importance of reading, the verbal section's name was changed to the Critical Reading section.
In March 2006, it was announced that a small percentage of the SATs taken in October 2005 had been scored incorrectly due to the test papers' being moist and not scanning properly, and that some students had received erroneous scores. The College Board announced they would change the scores for the students who were given a lower score than they earned, but at this point many of those students had already applied to colleges using their original scores. The College Board decided not to change the scores for the students who were given a higher score than they earned. A lawsuit was filed in 2006 on behalf of the 4,411 students who received an incorrect score on the SAT. The class-action suit was settled in August 2007, when the College Board and Pearson Educational Measurement, the company that scored the SATs, announced they would pay $2.85 million into a settlement fund. Under the agreement, each student could either elect to receive $275 or submit a claim for more money if he or she felt the damage was greater. A similar scoring error occurred on a secondary school admission test in 2010–2011, when the ERB (Educational Records Bureau) announced, after the admission process was over, that an error had been made in the scoring of the tests of 2010 students (17%), who had taken the Independent School Entrance Examination for admission to private secondary schools for 2011. Commenting on the effect of the error on students' school applications in The New York Times, David Clune, President of the ERB stated "It is a lesson we all learn at some point—that life isn't fair."
As part of an effort to “reduce student stress and improve the test-day experience", in late 2008 the College Board announced that the Score Choice option, recently dropped for SAT subject exams, would be available for both the SAT subject tests and the SAT starting in March, 2009. At the time, some college admissions officials agreed that the new policy would help to alleviate student test anxiety, while others questioned whether the change was primarily an attempt to make the SAT more competitive with the ACT, which had long had a comparable score choice policy. Recognizing that some colleges would want to see the scores from all tests taken by a student, under this new policy, the College Board would encourage but not force students to follow the requirements of each college to which scores would be sent. A number of highly selective colleges and universities, including Yale, the University of Pennsylvania, Cornell, and Stanford, rejected the Score Choice option at the time and continue to require applicants to submit all scores. Others, such as MIT and Harvard, allow students to choose which scores they submit, and use only the highest score from each section when making admission decisions. Still others, such as Oregon State University and University of Iowa, allow students to choose which scores they submit, considering only the test date with the highest combined score when making admission decisions.
Beginning in the fall of 2012, test takers were required to submit a current, recognizable photo during registration. In order to be admitted to their designated test center, students were required to present their photo admission ticket – or another acceptable form of photo ID – for comparison to the one submitted by the student at the time of registration. The changes were made in response to a series of cheating incidents, primarily at high schools in Long Island, New York, in which high-scoring test takers were using fake photo IDs to take the SAT for other students. In addition to the registration photo stipulation, test takers were required to identify their high school, to which their scores as well as the submitted photos would be sent. In the event of an investigation involving the validity of a student's test scores, his or her photo may be made available to institutions to which they have sent scores. Any college that is granted access to a student's photo is first required to certify that they are all admitted students.
On March 5, 2014, the College Board announced its plan to redesign the SAT in order to link the exam more closely to the work high school students encounter in the classroom. The new exam was administered for the first time in March 2016. Some of the major changes are: an emphasis on the use of evidence to support answers, a shift away from obscure vocabulary to words that students are more likely to encounter in college and career, a math section that is focused on fewer areas, a return to the 1600-point score scale, an optional essay, and the removal of penalty for wrong answers (rights-only scoring). To combat the perceived advantage of costly test preparation courses, the College Board announced a new partnership with Khan Academy to offer free online practice problems and instructional videos.
The SAT has been renamed several times since its introduction in 1926. It was originally known as the Scholastic Aptitude Test. In 1990, a commission set up by the College Board to review the proposed changes to the SAT program recommended that the meaning of the initialism SAT be changed to "Scholastic Assessment Test" because a "test that integrates measures of achievement as well as developed ability can no longer be accurately described as a test of aptitude". In 1993, the College Board changed the name of the test to SAT I: Reasoning Test; at the same time, the name of the Achievement Tests was changed to SAT II: Subject Tests. The Reasoning Test and Subject Tests were to be collectively known as the Scholastic Assessment Tests. According to the president of the College Board at the time, the name change was meant "to correct the impression among some people that the SAT measures something that is innate and impervious to change regardless of effort or instruction." The new SAT debuted in March 1994, and was referred to as the Scholastic Assessment Test by major news organizations. However, in 1997, the College Board announced that the SAT could not properly be called the Scholastic Assessment Test, and that the letters SAT did not stand for anything. In 2004, the Roman numeral in SAT I: Reasoning Test was dropped, making SAT Reasoning Test the new name of the SAT.
In 2002, Richard Rothstein (education scholar and columnist) wrote in The New York Times that the U.S. math averages on the SAT and ACT continued their decade-long rise over national verbal averages on the tests.
The College Board has been accused of completely reusing old SAT papers previously given in the United States. The recycling of questions from previous exams has been exploited to allow for cheating on exams and impugned the validity of some students' test scores, according to college officials. Test preparation companies in Asia have been found to provide test questions to students within hours of a new SAT exam's administration.
On August 25, 2018, the SAT test given in America was discovered to be a recycled October 2017 international SAT test given in China. The leaked PDF file was on the internet before the August 25, 2018 exam.
For decades many critics have accused designers of the verbal SAT of cultural bias as an explanation for the disparity in scores between poorer and wealthier test-takers. A famous (and long past) example of this bias in the SAT I was the oarsman–regatta analogy question. The object of the question was to find the pair of terms that had the relationship most similar to the relationship between "runner" and "marathon". The correct answer was "oarsman" and "regatta". The choice of the correct answer was thought to have presupposed students' familiarity with rowing, a sport popular with the wealthy. However, according to Murray and Herrnstein, the black-white gap is smaller in culture-loaded questions like this one than in questions that appear to be culturally neutral. Analogy questions have since been replaced by short reading passages.
A report from The New York Times stated that family income can explain much of the variance in SAT scores. In response, Lisa Wade, contributor at the website The Society Pages, commented that those with higher family income, “tend to have better teachers, more resource-rich educational environments, more educated parents who can help them with school and, sometimes, expensive SAT tutoring.” However, University of California system research found that after controlling for family income and parental education, the already low ability of the SAT to measure aptitude and college readiness fell sharply while the more substantial aptitude and college readiness measuring abilities of high school GPA and the SAT II each remained undiminished (and even slightly increased). The University of California system required both the SAT and the SAT II from applicants to the UC system during the four years included in the study. They further found that, after controlling for family income and parental education, the so-called achievement tests known as the SAT II measure aptitude and college readiness 10 times higher than the SAT. As with racial bias, correlation with income could also be due to the social class of the makers of the test, although according to the authors of The Bell Curve, empirical research suggests that poorer students actually perform worse on questions the authors believed to be "neutral" compared to the ones they termed as "privileged."
The largest association with gender on the SAT is found in the math section, where male students, on average, score higher than female students by approximately 30 points. In 2013, the American College Testing Board released a report stating that boys outperformed girls on the mathematics section of the test.
Some researchers believe that the difference in scores for both race and gender is closely related to psychological phenomenon known as stereotype threat. Stereotype threat happens when an individual who identifies themselves within a subgroup of people, is taking a test and comes across a stereotype (usually of American origin) regarding their subgroup. This along with additional test anxiety, will usually cause a low test performance for that individual or group affected. This is because the individual is under increased pressure to overcome the stereotype threat and prove it wrong.This form of stereotype can be translated into a form of gender or race bias and is found in numerous SAT tests spanning throughout the years it has existed. Gender bias of the SAT tests can happen within certain sections which include the questions or passages themselves. This bias itself is usually for that against females. Specific examples of this can be seen in the demographics, verbal/reading and mathematics portions of the SAT tests.. Other researchers question this assertion, and point to evidence in support of greater male variability in spatial ability and mathematics. Greater male variability has been found in both body weight, height, and cognitive abilities across cultures, leading to a larger number of males in the lowest and highest distributions of testing. This results in a higher number of males scoring in the upper extremes of mathematics tests such as the SAT, resulting in the gender discrepancy.
For the demographics example, students are often asked to identify their race or gender before taking the exam, just this alone is enough to create the threat since this puts the issues regarding their gender or race in front and center of their mind.
For the mathematics example, a question in the May 2016 SAT test involved a chart which identified more boys than girls in mathematics classes overall. Due to this, the girls taking the test might feel that mathematics is not for them and may even feel as if they are not intelligent enough to complete to engage in mathematics and/or the question itself. This is also based on the common stereotype that "men are better at math than women,"
For the verbal/reading example, a question in the May 2016 SAT test asked students to analyze and interpret a 19th century polemic arguing that women's place was at home. The reading passage itself was paired with 1837's “Essay on Slavery and Abolitionism” by Catherine E. Beecher with an 1838 reply from Angelina E Grimké, who was an abolitionist at the time. The Beecher essays argued that women have a lower stature than men and are able to be their best when in domestic situations while Grimké argue that no one's right's should be crippled just because of their gender. The questions regarding the passages are considered by critics to be of mutual ground but it's the placement of these passages that may have been the real issue. Since the passages were in the beginning it may have allowed this new information to linger in the minds of the test takers for the rest of their test taking time, especially the females who may now have the new thought as to not being intellectually competent of doing things other than house work and chores.
Studies suggest that teaching about stereotype threat might offer a practical means of reducing its detrimental effects. It can be shown when women were informed about stereotype threat problems in standardized tests, they tend to achieve higher scores. Thus, informing women about stereotype threat may be a useful intervention to improve their performance in a threatening testing situation. This is also known as a stereotype threat mitigation. The main study that supports these findings comes from two well-known professionals on Education known as Claude Steele and Steve Spencer. For their study, they created a test which was a close replication to the math portion on SAT or GRE exams. With this test, one group from each gender would be given the test with an intro sentence.The other group within each gender would not be given this sentence. The sentence itself stated: you may have heard that women don't do as well as men on difficult standardized math tests, but that's not true for the particular standardized math test; on this particular test, women always do as well as men. The results were as follows: among participants who weren't given the intro sentence, where the women could still feel the threat of stigma confirmation, women did worse than equally skilled men. But among participants who were given the intro sentence that stated the test did not show gender differences, where the women were free of confirming anything about being a woman, woman performed at the same high level as equally skilled men. Their under-performance was eliminated. In another study, researchers created a similar mock SAT math section exam which had both men and women complete difficult math problems described either as a problem-solving task or as a math test. In a third (teaching-intervention) condition, the test was also described as a math test, but participants were additionally informed that stereotype threat could interfere with women's math performance and that the threat itself shouldn't be considered to be true for any woman. Results showed that women performed worse than men when the problems were described as a math test (where the stereotype threat was not discussed), but did not differ from men in the problem-solving condition or the men that learned about stereotype threat. For the women in the teaching-intervention condition in which they learned about the threat, they indeed had a greater overall performance than the women without this treatment.
Although aspects of testing such as stereotype are a concern, research on the predictive validity of the SAT has demonstrated that it tends to be a more accurate predictor of female GPA in university as compared to male GPA.
Researchers believe that the difference in scores is closely related to the overall achievement gap in American society between students of different racial groups. This gap may be explainable in part by the fact that students of disadvantaged racial groups tend to go to schools that provide lower educational quality. This view is supported by evidence that the black-white gap is higher in cities and neighborhoods that are more racially segregated. It has also been suggested that stereotype threat has a significant effect on lowering achievement of minority students. For example, African Americans perform worse on a test when they are told that the test measures "verbal reasoning ability", than when no mention of the test subject is made. Other research cites poorer minority proficiency in key coursework relevant to the SAT (English and math), as well as peer pressure against students who try to focus on their schoolwork ("acting white"). Cultural issues are also evident among black students in wealthier households, with high achieving parents. John Ogbu, a Nigerian-American professor of anthropology, found that instead of looking to their parents as role models, black youth chose other models like rappers and did not put forth the effort to be good students.
One set of studies has reported differential item functioning – namely, some test questions function differently based on the racial group of the test taker, reflecting some kind of systematic difference in a groups ability to understand certain test questions or to acquire the knowledge required to answer them. In 2003 Freedle published data showing that Black students have had a slight advantage on the verbal questions that are labeled as difficult on the SAT, whereas white and Asian students tended to have a slight advantage on questions labeled as easy. Freedle argued that these findings suggest that "easy" test items use vocabulary that is easier to understand for white middle class students than for minorities, who often use a different language in the home environment, whereas the difficult items use complex language learned only through lectures and textbooks, giving both student groups equal opportunities to acquiring it.  The study was severely criticized by the ETS board, but the findings were replicated in a subsequent study by Santelices and Wilson in 2010.
There is no evidence that SAT scores systematically underestimate future performance of minority students. However, the predictive validity of the SAT has been shown to depend on the dominant ethnic and racial composition of the college. Some studies have also shown that African American students under-perform in college relative to their white peers with the same SAT scores; researchers have argued that this is likely because white students tend to benefit from social advantages outside of the educational environment (for example, high parental involvement in their education, inclusion in campus academic activities, positive bias from same-race teachers and peers) which result in better grades.
Christopher Jencks concludes that as a group, African Americans have been harmed by the introduction of standardized entrance exams such as the SAT. This, according to him, is not because the tests themselves are flawed, but because of labeling bias and selection bias; the tests measure the skills that African Americans are less likely to develop in their socialization, rather than the skills they are more likely to develop. Furthermore, standardized entrance exams are often labeled as tests of general ability, rather than of certain aspects of ability. Thus, a situation is produced in which African American ability is consistently underestimated within the education and workplace environments, contributing in turn to selection bias against them which exacerbates underachievement.
In the 1960s and 1970s there was a movement to drop achievement scores. After a period of time, the countries, states and provinces that reintroduced them agreed that academic standards had dropped, students had studied less, and had taken their studying less seriously. They reintroduced the tests after studies and research concluded that the high-stakes tests produced benefits that outweighed the costs.
Anyone involved in education should be concerned about how overemphasis on the SAT is distorting educational priorities and practices, how the test is perceived by many as unfair, and how it can have a devastating impact on the self-esteem and aspirations of young students. There is widespread agreement that overemphasis on the SAT harms American education.
Even now, no firm conclusions can be reached regarding the SAT's usefulness in the admissions process. It may or may not be biased, and it may or may not serve as a check on grade inflation in secondary schools.
Frey and Detterman (2003) investigated associations of SAT scores with intelligence test scores. Using an estimate of general mental ability, or g, based on the Armed Services Vocational Aptitude Battery, which can be best thought of as representing crystallized intelligence (learned abilities), they found SAT scores to be highly correlated with g (r=.82 in their sample, .857 when adjusted for non-linearity) in their sample taken from a 1979 national probability survey. Additionally, they investigated the correlation between SAT results, using the revised and recentered form of the test, and scores on the Raven's Advanced Progressive Matrices, a test of fluid intelligence (reasoning), this time using a non-random sample. They found that the correlation of SAT results with scores on the Raven's Advanced Progressive Matrices was .483. They estimated that this latter correlation would have been about 0.72 were it not for the restriction of ability range in the sample. They also noted that there appeared to be a ceiling effect on the Raven's scores which may have suppressed the correlation. Beaujean and colleagues (2006) have reached similar conclusions to those reached by Frey and Detterman.
SAT preparation is a highly lucrative field. The field was pioneered by Stanley Kaplan, whose SAT preparation course began in 1946 as a 64-hour course. Many companies and organizations offer test preparation in the form of books, classes, online courses, and tutoring. The test preparation industry began almost simultaneously with the introduction of university entrance exams in the U.S. and flourished from the start.
The College Board maintains that the SAT is essentially uncoachable and research by the College Board and the National Association of College Admission Counseling suggests that tutoring courses result in an average increase of about 20 points on the math section and 10 points on the verbal section. Other studies have shown significantly different results. A longitudinal study from Ohio State showed that taking private SAT prep classes correlated with scores higher by ~60 points. A study from Oxford showed that coaching courses boosted scores by an average of 56 points.
Montgomery and Lilly (2012) performed a systematic literature review of all published SAT coaching research in search of high quality studies (defined as those with randomized controlled trials). They found that the randomized treatments resulted in V/M gains of +23/32 points for a total of +56; the high quality study that showed the highest score increase was Johnson (1984; San Francisco) which was based on a 30-hour prep course that showed an average increase of 178 points. The Johnson San Francisco study was also the only high quality study found on a prep course of 30 hours or more in length, although validity of this outlier study is uncertain due to the attrition of half the participants.
Certain high IQ societies, like Mensa, the Prometheus Society and the Triple Nine Society, use scores from certain years as one of their admission tests. For instance, the Triple Nine Society accepts scores (verbal and math combined) of 1450 or greater on SAT tests taken before April 1995, and scores of at least 1520 on tests taken between April 1995 and February 2005.
The SAT is sometimes given to students younger than 13 by organizations such as the Study of Mathematically Precocious Youth, Johns Hopkins Center for Talented Youth, Duke TIP, and other organizations who use the results to select, study and mentor students of exceptional ability.
In 2005, MIT Writing Director Pavan Sreekireddy plotted essay length versus essay score on the new SAT from released essays and found a high correlation between them. After studying over 50 graded essays, he found that longer essays consistently produced higher scores. In fact, he argues that by simply gauging the length of an essay without reading it, the given score of an essay could likely be determined correctly over 90% of the time. He also discovered that several of these essays were full of factual errors; the College Board does not claim to grade for factual accuracy.
Perelman, along with the National Council of Teachers of English also criticized the 25-minute writing section of the test for damaging standards of writing teaching in the classroom. They say that writing teachers training their students for the SAT will not focus on revision, depth, accuracy, but will instead produce long, formulaic, and wordy pieces. "You're getting teachers to train students to be bad writers", concluded Perelman.
He said he also wanted to make the test reflect more closely what students did in high school
The ACT (; originally an abbreviation of American College Testing) is a standardized test used for college admissions in the United States. It was first introduced in November 1959 by University of Iowa professor Everett Franklin Lindquist as a competitor to the Scholastic Aptitude Test (SAT). It is currently administered by ACT, a nonprofit organization of the same name.The ACT originally consisted of four tests: English, Mathematics, Social Studies, and Natural Sciences. In 1989, however, the Social Studies test was changed into a Reading section (which included a social sciences subsection), and the Natural Sciences test was renamed the Science Reasoning test, with more emphasis on problem-solving skills as opposed to memorizing scientific facts. In February 2005, an optional Writing Test was added to the ACT, mirroring changes to the SAT that took place in March of the same year. In 2013, ACT announced that students would be able to take the ACT by computer starting in the spring of 2015; however, by the fall of 2017, computer-based ACT tests were available only for school-day testing in limited school districts in the US, with greater availability not expected until at least the fall of 2018.The ACT has seen a gradual increase in the number of test takers since its inception, and in 2011 the ACT surpassed the SAT for the first time in total test takers; that year, 1,666,017 students took the ACT and 1,664,479 students took the SAT. All four-year colleges and universities in the U.S. accept the ACT, but different institutions place different emphases on standardized tests such as the ACT, compared to other factors including class rank, GPA, and extracurricular activities.
The main four sections are individually scored on a scale of 1–36, and a composite score (the rounded whole number average of the four sections) is provided.Anti-satellite weapon
Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for strategic military purposes. Several nations possess operational ASAT systems. Although no ASAT system has yet been utilised in warfare, a few nations have shot down their own satellites to demonstrate their ASAT capabilities in a show of force. Only the United States, Russia, China, and India have demonstrated this capability successfully.Boolean satisfiability problem
In computer science, the Boolean satisfiability problem (sometimes called propositional satisfiability problem and abbreviated SATISFIABILITY or SAT) is the problem of determining if there exists an interpretation that satisfies a given Boolean formula. In other words, it asks whether the variables of a given Boolean formula can be consistently replaced by the values TRUE or FALSE in such a way that the formula evaluates to TRUE. If this is the case, the formula is called satisfiable. On the other hand, if no such assignment exists, the function expressed by the formula is FALSE for all possible variable assignments and the formula is unsatisfiable. For example, the formula "a AND NOT b" is satisfiable because one can find the values a = TRUE and b = FALSE, which make (a AND NOT b) = TRUE. In contrast, "a AND NOT a" is unsatisfiable.
SAT is the first problem that was proven to be NP-complete; see Cook–Levin theorem. This means that all problems in the complexity class NP, which includes a wide range of natural decision and optimization problems, are at most as difficult to solve as SAT. There is no known algorithm that efficiently solves each SAT problem, and it is generally believed that no such algorithm exists; yet this belief has not been proven mathematically, and resolving the question of whether SAT has a polynomial-time algorithm is equivalent to the P versus NP problem, which is a famous open problem in the theory of computing.
Nevertheless, as of 2007, heuristic SAT-algorithms are able to solve problem instances involving tens of thousands of variables and formulas consisting of millions of symbols, which is sufficient for many practical SAT problems from, e.g., artificial intelligence, circuit design, and automatic theorem proving.Canal (TV provider)
Canal is a French subscription provider. It is owned by Vivendi (owner of Canal) with a hundred percent share.College Board
College Board is an American not-for-profit organization that was formed in December 1899 as the College Entrance Examination Board (CEEB) to expand access to higher education. While College Board is not an association of colleges, it runs a membership association of institutions, including over 6,000 schools, colleges, universities and other educational organizations.
College Board develops and administers standardized tests and curricula used by K–12 and post-secondary education institutions to promote college-readiness and as part of the college admissions process. College Board is headquartered in New York City. David Coleman has been the president of College Board since October 2012. He replaced Gaston Caperton, former Governor of West Virginia, who had held this position since 1999.In addition to managing assessments for which it charges fees, College Board provides resources, tools, and services to students, parents, colleges and universities in the areas of college planning, recruitment and admissions, financial aid, and retention. It is partly funded by grants from various foundations, such as the Bill and Melinda Gates Foundation until 2009.Communications satellite
A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are 2,134 communications satellites in Earth’s orbit, used by both private and government organizations. Many are in geostationary orbit 22,200 miles (35,700 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.
The high frequency radio waves used for telecommunications links travel by line of sight and so are obstructed by the curve of the Earth. The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites use a wide range of radio and microwave frequencies. To avoid signal interference, international organizations have regulations for which frequency ranges or "bands" certain organizations are allowed to use. This allocation of bands minimizes the risk of signal interference.CubeSat
A CubeSat (U-class spacecraft) is a type of miniaturized satellite for space research that is made up of multiples of 10 cm × 10 cm × 11.35 cm (~ 4 in × 4 in × 4.5 in) cubic units. CubeSats have a mass of no more than 1.33 kilograms (2.9 lb) per unit, and often use commercial off-the-shelf (COTS) components for their electronics and structure. CubeSats are commonly put in orbit by deployers on the International Space Station, or launched as secondary payloads on a launch vehicle. Over 1000 CubeSats have been launched as of January 2019. Over 900 have been successfully deployed in orbit and over 80 have been destroyed in launch failures.In 1999, California Polytechnic State University (Cal Poly) and Stanford University developed the CubeSat specifications to promote and develop the skills necessary for the design, manufacture, and testing of small satellites intended for low Earth orbit (LEO) that perform a number of scientific research functions and explore new space technologies. Academia accounted for the majority of CubeSat launches until 2013, when more than half of launches were for non-academic purposes, and by 2014 most newly deployed CubeSats were for commercial or amateur projects.
Uses typically involve experiments that can be miniaturized or serve purposes such as Earth observation or amateur radio. CubeSats are employed to demonstrate spacecraft technologies intended for small satellites or that present questionable feasibility and are unlikely to justify the cost of a larger satellite. Scientific experiments with unproven underlying theory may also find themselves aboard CubeSats because their low cost can justify higher risks. Biological research payloads have been flown on several missions, with more planned. Several missions to the Moon and Mars are planning to use CubeSats. In May 2018, the two MarCO CubeSats became the first CubeSats to leave Earth orbit, on their way to Mars alongside the successful InSight mission.Some CubeSats became the first national satellites of their countries, being launched by universities, state, or private companies. The searchable Nanosatellite and CubeSat Database lists over 2,000 CubeSats that have been and are planned to be launched since 1998.Intelsat
Intelsat Corporation—formerly INTEL-SAT, INTELSAT, Intelsat—is a communications satellite services provider. Originally formed as International Telecommunications Satellite Organization (ITSO, or INTELSAT), it was—from 1964 to 2001—an intergovernmental consortium owning and managing a constellation of communications satellites providing international broadcast services.
As of March 2011, Intelsat operates a fleet of 52 communications satellites, which is one of the world's largest fleet of commercial satellites. They claim to serve around 1,500 customers and employ a staff of approximately 1,100 people.List of Latin phrases (V)
This page lists English translations of notable Latin phrases, such as veni vidi vici and et cetera. Some of the phrases are themselves translations of Greek phrases, as Greek rhetoric and literature reached its peak centuries before the rise of ancient Rome.
This list covers the letter V. See List of Latin phrases for the main list.Oxygen saturation
Oxygen saturation (symbol SO2) is a relative measure of the concentration of oxygen that is dissolved or carried in a given medium as a proportion of the maximal concentration that can be dissolved in that medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water. The standard unit of oxygen saturation is percent (%).
Oxygen saturation can be measured regionally and noninvasively. Arterial oxygen saturation (SaO2) is commonly measured using pulse oximetry. Tissue saturation at peripheral scale can be measured using NIRS. This technique can be applied on both muscle and brain.Paulo Coelho
Paulo Coelho de Souza (; Portuguese: [ˈpawlu kuˈeʎu]; born 24 August 1947) is a Brazilian lyricist and novelist. He is best known for his novel The Alchemist. In 2014, he uploaded his personal papers online to create a virtual Paulo Coelho Foundation.Peerage of Ireland
The Peerage of Ireland consists of those titles of nobility created by the English monarchs in their capacity as Lord or King of Ireland, or later by monarchs of the United Kingdom of Great Britain and Ireland. The creation of such titles came to an end in the 19th century. The ranks of the Irish peerage are Duke, Marquess, Earl, Viscount and Baron. As of 2016, there were 135 titles in the Peerage of Ireland extant: two dukedoms, ten marquessates, 43 earldoms, 28 viscountcies, and 52 baronies. The Crown of the United Kingdom of Great Britain & Northern Ireland continues to exercise jurisdiction over the Peerage of Ireland, including those peers whose titles derive from places located in what is now the Republic of Ireland. Article 40.2 of the Irish Constitution forbids the state conferring titles of nobility and a citizen may not accept titles of nobility or honour except with the prior approval of the Government. As stated above, this issue does not arise in respect of the Peerage of Ireland, as no creations of titles in it have been made since the Constitution came into force.
In the following table, each peer is listed only by his or her highest Irish title, showing higher or equal titles in the other peerages. Those peers who are known by a higher title in one of the other peerages are listed in italics.Reconnaissance satellite
A reconnaissance satellite or intelligence satellite (commonly, although unofficially, referred to as a spy satellite) is an Earth observation satellite or communications satellite deployed for military or intelligence applications.
The first generation type (i.e., Corona
and Zenit) took photographs, then ejected canisters of photographic film which would descend to earth. Corona capsules were retrieved in mid-air as they floated down on parachutes. Later, spacecraft had digital imaging systems and downloaded the images via encrypted radio links.
In the United States, most information available is on programs that existed up to 1972, as this information has been declassified due to its age. Some information about programs prior to that time is still classified, and a small amount of information is available on subsequent missions.
A few up-to-date reconnaissance satellite images have been declassified on occasion, or leaked, as in the case of KH-11 photographs which were sent to Jane's Defence Weekly in 1984.San Antonio International Airport
San Antonio International Airport (IATA: SAT, ICAO: KSAT, FAA LID: SAT) is an international airport in San Antonio, Texas. It is in Uptown Central San Antonio, about 8 miles north of Downtown. It has three runways and covers 2,305 acres (933 ha). Its elevation is 809 feet (247 m) above sea level.
SAT averages 260 daily departures and arrivals at its 25 gates, which serve 12 airlines flying non-stop to 53 destinations in the US, Mexico and Canada. In 2017 more than 9 million travelers passed through San Antonio, a record for the airport. It was ranked behind Texas airports in Dallas/Fort Worth, Houston and Austin but ahead of El Paso.Sat.1
Sat.1 is a German free-to-air television channel that is considered the first privately-owned television network in Germany, having been launched in January 1984 as PKS (Programmgesellschaft für Kabel- und Satellitenrundfunk), initially a joint venture of various publishing houses, and was rebranded as Sat.1 in January 1985. The first broadcast could only be seen by roughly 1200 households who had cable access in the city of Ludwigshafen. Early programs included old films (mainly from the archives of KirchMedia) American hit series and game shows (the most notable show being the German version of Wheel of Fortune, Glücksrad). Later, the station acquired a name for its original series and TV films.
Sat.1 is a part of the ProSiebenSat.1 Media Group. Pay-TV sister channel Sat.1 Emotions (formerly Sat.1 Comedy) airs comedy, romance and movies. In 2013 Sat.1 Gold, a second, free-to-air Sat.1 offshoot was also launched.In addition to its free-to-air standard definition feed, Sat.1 also broadcasts an HD feed as a subscription-only channel, available on Astra's HD+ satellite pay-TV platform.Satellite navigation
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows small electronic receivers to determine their location (longitude, latitude, and altitude/elevation) to high precision (within a few metres) using time signals transmitted along a line of sight by radio from satellites. The system can be used for providing position, navigation or for tracking the position of something fitted with a receiver (satellite tracking). The signals also allow the electronic receiver to calculate the current local time to high precision, which allows time synchronisation. Satnav systems operate independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the positioning information generated.
A satellite navigation system with global coverage may be termed a global navigation satellite system (GNSS). As of October 2018, the United States' Global Positioning System (GPS) and Russia's GLONASS are fully operational GNSSs, with China's BeiDou Navigation Satellite System (BDS) and the European Union's Galileo scheduled to be fully operational by 2020. India, France and Japan are in the process of developing regional navigation and augmentation systems as well.
Global coverage for each system is generally achieved by a satellite constellation of 18–30 medium Earth orbit (MEO) satellites spread between several orbital planes. The actual systems vary, but use orbital inclinations of >50° and orbital periods of roughly twelve hours (at an altitude of about 20,000 kilometres or 12,000 miles).Satellite phone
A satellite telephone, satellite phone or satphone is a type of mobile phone that connects to other phones or the telephone network by radio through orbiting satellites instead of terrestrial cell sites, as cellphones do. The advantage of a satphone is that its use is not limited to areas covered by cell towers; it can be used in most or all geographic locations on the Earth's surface.
The mobile equipment, also known as a terminal, varies widely. Early satellite phone handsets had a size and weight comparable to that of a late-1980s or early-1990s mobile phone, but usually with a large retractable antenna. More recent satellite phones are similar in size to a regular mobile phone while some prototype satellite phones have no distinguishable difference from an ordinary smartphone. Satphones are popular on expeditions into remote areas where terrestrial cellular service is unavailable.
A fixed installation, such as one used aboard a ship, may include large, rugged, rack-mounted electronics, and a steerable microwave antenna on the mast that automatically tracks the overhead satellites. Smaller installations using VoIP over a two-way satellite broadband service such as BGAN or VSAT bring the costs within the reach of leisure vessel owners. Internet service satellite phones have notoriously poor reception indoors, though it may be possible to get a consistent signal near a window or in the top floor of a building if the roof is sufficiently thin. The phones have connectors for external antennas that can be installed in vehicles and buildings. The systems also allow for the use of repeaters, much like terrestrial mobile phone systems.Shudra
Shudra or Shoodra is the fourth varna, or one of the four social categories found in the texts of Hinduism. Various sources translate it into English as a caste, or alternatively as a social class. It is the lowest rank of the four varnas.The word Shudra appears only once in the Rig veda but is found in other Hindu texts such as the Manusmriti, Arthashastra and Dharmashastras. Theoretically, Shudras have constituted the hereditary labouring class serving others. In some cases, they participated in the coronation of kings, or were ministers and kings according to early Indian texts.Standard score
In statistics, the standard score is the signed fractional number of standard deviations by which the value of an observation or data point is above the mean value of what is being observed or measured. Observed values above the mean have positive standard scores, while values below the mean have negative standard scores.
It is calculated by subtracting the population mean from an individual raw score and then dividing the difference by the population standard deviation. It is a dimensionless quantity. This conversion process is called standardizing or normalizing (however, "normalizing" can refer to many types of ratios; see normalization for more).
Standard scores are also called z-values, z-scores, normal scores, and standardized variables. They are most frequently used to compare an observation to a theoretical deviate, such as a standard normal deviate.
Computing a z-score requires knowing the mean and standard deviation of the complete population to which a data point belongs; if one only has a sample of observations from the population, then the analogous computation with sample mean and sample standard deviation yields the t-statistic.
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