Question

An English professor is attempting to estimate the mean number of novels that the student body reads during their time in college. He is conducting an exit survey with seniors. He hopes to have a margin of error of 2 books with 90​% confidence. From reading previous​ studies, he expects a large standard deviation and is going to assume it is 7. How many students should he​ survey?

Answer 1

Solution :

Given that,

Standard deviation = = 7

Margin of error = E = 2

Z/2 = 1.645

sample size = n = [Z/2* / E] 2

n = [1.645 * 7 / 2]2

n = 33.15

He should survey = 34 students