4) A student's grade is 65 where the mean is 55 and standard deviation is 10. The proportion of the student population who would score higher than 65 is about:
A) 34%
B) 68%
C) 16%
D) 2.5%

Question

Quizplus · Accepted Answer

Using the standard normal distribution, we find the z-score of the student's grade:

z = (65-55)/10 = 1

Looking at a standard normal table, we find that the proportion of the population that would score higher than 65 is approximately 16%, which corresponds to a z-score of 1 or higher. Therefore, the answer is C.

4) a Student's Grade Is 65 Where the Mean Is