Question

A study looked into average money spent eating out each week. Average money spent was $127 with sample standard deviation of $32. There were 25 samples in the study. Find the 95% confidence interval. What is the smaller value of the confidence interval?

Answer 1

The 95% confidence interval is: CI = (114.456, 139.544)

The smaller value of the confidence interval is: 139.544

How to find the Confidence Interval?

The formula to find confidence interval is:

CI = x' ± z(s/√n)

where:

CI = confidence interval

x' = sample mean

z = confidence level value

s = sample standard deviation

n = sample size

Thus, we are given:

x' = 127

s = 32

n = 25

z at 95% CL = 1.96

Thus:

CI = 127 ± 1.96(32/√25)

CI = 127 ± 12.544

CI = (114.456, 139.544)