Several hundred students enrolled in introductory statistics courses at a large university were surveyed and asked if they smoked. Smokers were to report how many cigarettes they had smoked the day before.
a. Use software to access the survey data and construct a 95% confidence interval for the number of cigarettes smoked in a day by the smoking students.
b. Based on cigarette sales and percentage of people who smoked, the Centers for Disease Control estimates the number of cigarettes smoked per day by smokers in 1990 to be 30.3. Explain why your confidence interval provides evidence that the mean for the population of students is much less than this.
c. Based on the National Health Interview Survey of thousands of smokers, the Centers for Disease Control states that the self-reported number of cigarettes smoked per day by smokers in 1990 was 19.1. Explain why your confidence interval provides evidence that the mean for the population of students is much less than this.
d. Give a possible explanation for why the self-reported number of cigarettes smoked (19.1) is considerably smaller than what the actual number apparently was (30.3).
e. Give a possible explanation for why the mean number of cigarettes smoked in 2003 would be less than what it was in 1990.
f. Give a possible explanation for why the mean number of cigarettes smoked by college student smokers would be less than what it is for smokers in general.