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GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2508
Given Kudos: 1053
GPA: 3.39
The class mean score on a test was 60, and the standard deviation was
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10 Jan 2023, 01:34
10 Jan 2023, 01:34
Expert Reply
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Question Stats:
14% (00:56) correct
85% (01:10) wrong based on 7 sessions
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The class mean score on a test was 60, and the standard deviation was 15. If Jack's score was within 2 standard deviations of the mean, what is the lowest score he could have received?
(A) 30
(B) 31
(C) 45
(D) 90
(E) 89
(A) 30
(B) 31
(C) 45
(D) 90
(E) 89
GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2508
Given Kudos: 1053
GPA: 3.39
Re: The class mean score on a test was 60, and the standard deviation was
[#permalink]
12 Jan 2023, 21:59
12 Jan 2023, 21:59
Expert Reply
1 SD from the mean is ADDING and Subtracting the amount of standard deviation from the mean one time. 2 SD from the mean is ADDING and Subtracting TWICE.
for example in this question.
1SD from the mean ranges from 75 to 45, where 75 is within SD above the mean and 45 within 1SD below the mean
2SD=15 TWICE=30 from the mean, which is 90 to 30, where 90 is within 2 SD above the mean AND 30 is within 2 SD below the mean.
Answer: A
for example in this question.
1SD from the mean ranges from 75 to 45, where 75 is within SD above the mean and 45 within 1SD below the mean
2SD=15 TWICE=30 from the mean, which is 90 to 30, where 90 is within 2 SD above the mean AND 30 is within 2 SD below the mean.
Answer: A
gmatclubot
Re: The class mean score on a test was 60, and the standard deviation was [#permalink]
12 Jan 2023, 21:59
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