1. Egyptian researchers, Kamal et al. (1991), took a sample of 126 police officers subject to inhalation of vehicle exhaust in downtown Cairo and found an average blood level concentration of lead equal to 29.2 Hg/dl (X) with a standard deviation of 7.5 Hg/dl (Su). A sample of 50 policemen from a suburb, Abbasia, had an average concentration of 18.2 Hg/dl (X) and a standard deviation of 5.8 Hg/dl (Ss). Answer the below questions under the significance level a = .05. a. Find the confidence interval of the ratio of Su/S, and test the null hypothesis that there is no difference in variances of two groups. (8 pts) Tips: Fo.975 (49, 125) = 1.564, and F0.975 (125, 49) = 1.642. b. Using the result in a, form a confidence interval for the population difference and test the null hypothesis that there is no difference in the populations. (8 pts) =