Question

A sample of 64 is taken from a population, with the mean of the sample being

67 and the standard deviation of the sample being 8. What is the 95%
confidence interval for the mean of the population?

Answer 1

65.04<x<68.96

Explanation:

The confidence interval formula is expressed as;

CI = x ± z*s/√n

x is the mean = 67

z is the 95% z score = 1.96

s is the standard deviation = 8

n is the sample size = 64

Substitute;

CI = 67 ± 1.96*8/√64

CI = 67 ± 1.96*8/8

CI = 67 ± 1.96

CI = (67-1.96, 67+1.96)

CI = (65.04, 68.96)

Hence the confidence interval for the mean of the population is between 65.04<x<68.96