assume sapme were selected from two population that are normally distributed with unequel standard deviation 1. dertemine the point estimate of the difference between the two unknown population mean weights. 2 construct a 97% confidence interval of the difference between the two unknowns population weights. 3. test at 3 % confidence level if the two unknown population mean weightd are different.

1.3 Suppose that in a combined Statistics class of 450 students, a lecturer manages to measure the weights of 75 students who registered for STA 121, and 65 students who registered for STA 122. Let X be the weight variable of STA 121 students so that the average weight is 49, and the summation of the squares of the students' weights is 586884. Moreover let Y be the weight variable of STA 122 students so that the average weight is 60, and the summation of the squares of the students' weight is 595884. Assume that the