Question

A statistics practitioner would like to estimate a population mean to within 50 units with 99% confidence given that the population standard deviation is 250. What sample size should be used

Answer 1

Explanation:

Using the sample size formula

n= (zs/e)²

z is the z score at 99% = 2.58

s is the standard deviation = 250

e is the sample mean = 50

Substitute

n = (2.58×250/50)²

n = (2.58×5)²

n = (12.9)²

n=166.41

hence the sample size is 166.41