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The graph illustrates the distribution of test scores taken by College Algebra students. The maximum possible score on the test was 130, while the mean score was 72 and the standard deviation was 14. (34,13.5,2.35,0.15)

30
44
58
72
86
100
114
Distribution of Test Scores
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What is the approximate percentage students who scored between 58 and 86 on the test?
%

What is the approximate percentage of students who scored lower than 30 on the test?
%

What is the approximate percentage of students who scored less than 44 on the test?
%

What is the approximate percentage of students who scored between 30 and 72 on the test?
%

1 Answer

4 votes

difference from mean/14 is z-score

z<=-3 for a score of 28 (28-70)/14. This would be about 0.0013 or 0.13%

z<=-2 for a score of 42, and that is about 0.0228

z<=-1 for a score of 56 and +1 for a score of 84. That is about 68%

between 70 and 84 is a z-score between 0 and 1, and that is about 34%

Higher than 98 is greater than 2 standard deviations, and that is 2.28%

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