Question 757445
Which is relatively better a score of 84 on a psychology test or a score of 47 on an economics test? Scores on the psychology test have a mean of 91 and a standard deviation of 10. Scores on the economics test have a mean of 51 and a standard deviation of 6.

A. The psychology test score is relatively better because its z score is less than the z score for the economics test score.
B. The economics test score is relatively better because its z score is greater than the z score for the psychology test score.
C. The psychology test score is relatively better because its z score is greater than the z score for the economics test score.  
D. The economics test score is relatively better because its z score is less than the z score for the psychology test score.

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For this problem, you need to find the z-score for EACH test to compare which one is better.

To find z, apply the formula z = (score - mean)/standard deviation.

I help you on the first z-score for psychology:

z = (84 - 91)/10 = -0.7

Then you can find the z-score for economy score. Then you compare them. The higher z-score means relatively better.

Good luck! John