Scientists collect a simple random sample of 25 menthol cigarettes and 25 nonmenthol cigarettes. Both samples consist of cigarettes that are filtered, 100 mm long, and non-light. The menthol cigarettes have a mean nicotine amount of 0.87 mg and a standard deviation of 0.24 mg. The nonmenthol cigarettes have a mean nicotine amount 0.92 mg and a standard deviation of 0.25 mg. Construct a 95 % confidence interval estimate of the difference between the mean nicotine amount in menthol cigarettes and the mean nicotine amount in nonmenthol cigarettes. What does the result suggest about the effect of menthol?
