A study is done on the effectiveness of muscle growth from regular weight training. A random sample of 16 untrained people is given a weight training program to follow. At the end of the study, the 16 participants gained an average of 3.4 pounds of muscle with a standard deviation of 1.2 pounds. Use this sample data to construct a 90% confidence interval for the mean amount of muscle untrained people will gain on this program. You may assume that the variable is normally distributed. You must write a sentence interpretation that is specific to this problem.