A study of 55 patients with back pain reported that the mean

Last updated: 7/21/2022

A study of 55 patients with back pain reported that the mean duration of pain was 17.6 months. It is known that the standard deviation of duration of back pain is 5.1 months. Assuming that the duration of this problem is normally distributed in the population; determine a 99% confidence interval for the mean duration of back pain in the population.