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14 Aug 2025, 04:51
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Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
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Question Stats:
100% (01:05) correct
0% (00:00) wrong based on 1 sessions
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S is the set of all test scores in Ms. K’s class. T is the set of all test scores in Ms. K’s class, after Ms. K added 10 points to every test score in the class.
Quantity A
The standard deviation of set S
Quantity B
The standard deviation of set T.
Quantity A
The standard deviation of set S
Quantity B
The standard deviation of set T.
25 Aug 2025, 00:18
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Official Explanation
Standard deviation is a measure of the dispersion of the numbers on a list from the list’s mean, or average. When the teacher adds 10 points to every score, the scores and their average are all shifted upward by 10, but the spread of the test scores from their mean remains unchanged. Therefore, the standard deviation of the new set is the same as that of the original set, and (C) is correct. To compute an actual standard deviation will not be required on the GRE. The complicated formula involves subtracting every number on the list from the mean, then averaging the squares of these differences, and finally taking the square root.
Answer: B
Standard deviation is a measure of the dispersion of the numbers on a list from the list’s mean, or average. When the teacher adds 10 points to every score, the scores and their average are all shifted upward by 10, but the spread of the test scores from their mean remains unchanged. Therefore, the standard deviation of the new set is the same as that of the original set, and (C) is correct. To compute an actual standard deviation will not be required on the GRE. The complicated formula involves subtracting every number on the list from the mean, then averaging the squares of these differences, and finally taking the square root.
Answer: B
