SOLUTION: Which of the following exam scores is better relative to other students enrolled in the course? • A psychology exam grade of 85; the mean grade for the psychology exam is 92 with
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Question 1189495: Which of the following exam scores is better relative to other students enrolled in the course? • A psychology exam grade of 85; the mean grade for the psychology exam is 92 with a standard deviation of 3.5 • An economics exam grade of 67; the mean grade for the economics exam is 79 with a standard deviation of 8 • A chemistry exam grade of 62; the mean grade for the chemistry exam is 62 with a standard deviation of 5 Answer by ikleyn(52803) (Show Source):
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Which of the following exam scores is better relative to other students enrolled in the course?
(a) A psychology exam grade of 85; the mean grade for the psychology exam is 92 with a standard deviation of 3.5;
(b) An economics exam grade of 67; the mean grade for the economics exam is 79 with a standard deviation of 8;
(c) A chemistry exam grade of 62; the mean grade for the chemistry exam is 62 with a standard deviation of 5.
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For each exam/grade you should calculate its z-score; then compare three z-score to determine which one is higher.
Use the formula for z-score
Z =
where
Z = standard score
x = observed value
mu = mean of the sample
sigma = standard deviation of the sample
Use this formula separately for each case.
(a) = = -2;
(b) = = -1.5;
(c) = = 0.0.
So, the score is highest. It means that that the exam score is better (is the best) for this exam (c).
The three Z-scores are in this order < < .
