Question

Statistics Question...

(10 pts) If the mean exam score of a class was 75%, with a standard deviation of 15%, what percent of students would be expected score at or higher than 92%? Assume that the distribution of the scores is normal and the variable is random 7.

Answer 1

$\mu$ = 75

$\sigma$ = 15

To find P(X>92):

Z= (92 - 75)/15 =1.1333

Table of Area Under Standard Normal Curve gives area = 0.3708

So

P(X>92) = 0.5 - 0.3708 = 0.1292 = 12.92 %

So,

Answer is:

12.92 %