Chapter 10.2, Problem 24PB

Inhaling affect HONC? Refer to the previous exercise.

1. a. Show that the test statistic for H₀: μ₁ = μ₁ equals t = 11.7. If the population means were equal, explain why it would be nearly impossible by random variation to observe this large a test statistic.
2. b. What decision would you make about H₀, at common significance levels? Can you conclude which group had higher mean nicotine dependence? How?
3. c. State the assumptions for the inference in this exercise.

Nicotine dependence A study on nicotine dependence for teenage smokers obtained a random sample of seventh graders. The response variable was constructed from a questionnaire called the Hooked on Nicotine Checklist (HONC). This is a list of ten questions such as, “Have you ever tried to quit but couldn’t?” and “Is it hard to keep from smoking in places where it is banned, like school?” The HONC score is the total number of questions to which a student answered yes, so each student’s HONC score falls between 0 and 10. The higher the score, the more hooked that student is on nicotine. One explanatory variable considered in the study was whether a subject reported inhaling when smoking. The following table reports descriptive statistics.