Question

We are interested in the amount of coffee that men and women drink. We take a simple random sample of 30 women and a simple random sample of 28 men. The sample of men drinks an average of 3.2 cups of coffee per day, with sample standard deviation 0.9 cups. The sample of women drinks an average of 3.5 cups of coffee per day, with sample standard deviation 1 cup. Assume that the samples are independent. Assume that the number of cups of coffee per day follows a Normal distribution for men and for women.

We would like to know if the average amount of coffee that women drink is more than 3 cups per day. Should we perform a z-test or t-test? What is the p-value?

A. z-test; p-value is 0.0031

B. z-test; p-value is 0.0062

C. t-test; p-value is between 0.005 and 0.01

D. t-test; p-value is between 0.01 and 0.02

Answer 1