Question: Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal.
|Filtered Kings||Nonfiltered Kings|
|n1 = 21||n2 = 8|
|x1 = 0.94||x2 = 1.65|
|s1 = 0.31||s2 = 0.16|
Refer to the sample results listed in the margin for the measure nicotine contents of randomly selected filtered and nonfiltered king-size cigarettes. All measurements are in milligrams, and the data are from the Federal Trade Commission.
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 of nicotine in nonfiltered king-size cigarettes.
b. Construct a 90% confidence interval estimate of the difference between the two population means.
c. Do cigarette filters appear to be effective in reducing nicotine?