Question

A survey was conducted that asked 1012 people how many books they had read in the past year. Results indicated that x overbarequals11.6 books and sequals16.6 books. Construct a 95​% confidence interval for the mean number of books people read. Interpret the interval.

Answer 1

Given that, sample size (n) = 1012, sample mean = 11.6 books

and standard deviation (s) = 16.6 books

A 95% confidence level has significance level of 0.05 and critical value is,

The 95% confidence interval for the population mean is,

Therefore, the 95% confidence interval for the mean number of books people read is (10.5772, 12.6228) books.

Interpretation : There is 95% confidence that the population mean number of books read is between 10.5772 and 12.6228.