The average American consumed 10.6 pounds of mozzarella cheese in 2009 (U.S. Department of Agriculture, February 20, 2012). Do male and female consumers differ in the amounts of mozzarella cheese they consume? The average consumption in a survey of 35 male consumers was 12.9 pounds, and the average consumption in a survey of 50 female consumers was 8.4 pounds. Based on past surveys, the standard deviation for male consumers is assumed to be 4.4 and the standard deviation for female consumers is assumed to be 3.1.

a. What is the point estimate of the difference between the population mean consumption for males and the population mean consumption for females?

b. At 99% confidence, what is the margin of error?

c. Develop a 99% confidence interval for the difference between the two population means.