Estimate Population Parameters 1. Two machines A and B are packaging 8-oz boxes of corn flakes. From past experience with the machines, it is assumed that the standard deviations of weights of the filling from the machines A and B are 0.04 oz and 0.05 oz, respectively. One hundred boxes filled by each machine are selected at random and the following is found: Machine A: nA Machine B: n 100, X = 8.18 oz 100, XB = 8.15 oz = 100, XB B HA - HB Find a 99% confidence interval for weights of fillings produced by machines A and B. the difference of the means of populations of 2. Ten determinations of percentage of water in a methanol solution yield X = 0.552 and S = 0.037f H S = 0.037ff is the "true" percentage of water in the imethanol solution, assuming normality, find (a) a 90% confidence interval for and (b) a 95% confidence interval for