Refer to the sample results below for the measured nicotine contents of randomly selected filtered and non-filtered king-size cigarettes. All measurements are in milligrams.
a. use a 0.05 significance level to test the claim that king-size cigarettes with filters have a lower mean amount of nicotine than the mean amount of nicotine in non-filtered king-size cigarettes.
b. Construct a 90% confidence interval estimate of the difference between the two population means.
c. Do cigarette filters seem to be effective in reducing nicotine?
Filtered Kings Non-filtered Kings
n 1 = 21 n 2 =8
x1 =0.94 x2 = 1.65
s1 = 0.31 s2 = 0.16