Question

A survey was conducted that asked 1008 people how many books they had read in the past year. Results indicated that xbar= 13.7 books and S= 16.6 books. Construct a 90% confidence interval for the mean number of books people read. Interpret the interval.

Answer 1

Given that, sample size (n) = 1008

sample mean = 13.7 books

sample standard deviation (s) = 16.6 books

A 90% confidence level has significance level of 0.10 and critical value is,

The 90% confidence interval for population mean is,

The 90% confidence interval is, (12.84, 14.56)

We are 90% confident that the mean number of books people read are between 12.84 and 14.56