A. In a study of high school students at least 16 years of age, researchers obtained the survey results summarized in the table below (based on data from â€œTexting While Driving and Other Risk Motor Vehicle Behaviors Among U.S. High School Studentsâ€ by Oâ€™Malley, Shults, and Eaton, Pediatrics, Vol. 131, No.6).
                                    Irregular Seat Belt Use?
                                                   Yes       No
Texted While Driving                   1737    2048
Did not Text While Driving          1945    2775
1. State the null and alternative hypotheses.
2. Assuming independence, what are the expected frequencies for each of these variables?
3. What is the value of the X2 statistic?
4. Use a 0.05 significance level to test the claim of independence between texting while driving and irregular seat belt use. Are those two risky behaviors independent of each other?
B. The Carolina Tobacco Company advertised that its best-selling, non-filtered cigarettes contained 40 milligrams of nicotine or less, but Consumer Advocate magazine ran tests on 10 randomly selected cigarettes and found the following amounts (in milligrams), shown below:
1)       47. 3 39.3 40.3 38.3 46.3 43.3 42.3 49.3 40.3 46.3
2) We can assume that the amount of nicotine in all cigarettes is normally distributed. Use a significance level of 0.05 to test the magazineâ€™s claim that the mean nicotine content of the Carolina Tobacco Companyâ€™s cigarettes is grater than 40 milligrams. Show your work.

A. In a study of high school students at least 16 years of age, res...