Question

In your psychology class, the mean exam score is 72 and the standard deviation is 12. You scored 78.

In your biology class, the mean exam score is 56 and the standard deviation is 5. You scored 66.

If your professors grade "on a curve" (i.e., according to the distribution of scores), for which exam would you expect to get a better grade?

(Hint: Convert your exam scores to z-scores).

A) Biology

B) Psychology

Answer 1

Solution :

Given that ,

mean = = 72 (Psychology )

standard deviation =  = 12

x = 78

Using z-score formula,

z = x - /   

z = 78 - 72 / 12

z = 0.50 ( Psychology)

mean = = 56 ( Biology )

standard deviation =  = 5

x = 66

Using z-score formula,

z = x - /   

z = 66 - 56 / 5

z = 2.00 ( Biology )

Biology exam would expect to get a better grade