1.A 1980 study was conducted whose purpose was to compare the indoor air quality in offices where smoking was permitted with that in offices where smoking was not permitted. Measurements were made of carbon monoxide (CO) at 1:20 p.m. in 40 work areas where smoking was permitted and in 40 work areas where smoking was not permitted. Where smoking was permitted, the mean CO level was 11.6 parts per million (ppm) and the standard deviation CO was 7.3 ppm. Where smoking was not permitted, the mean CO was 6.9 ppm and the standard deviation CO was 2.7 ppm. You can assume that the distribution of the CO measurements follow a normal-like distribution.

a)Test for whether the standard deviation of CO is significantly different in the two types of working environments.

b)Test for whether or not the mean CO is significantly different in the two types of working environments.

c)Provide a 95% CI for the difference in mean CO between the smoking and nonsmoking working environments.