In a study of adult smokers who wanted to quit, 657 subjects were randomly assigned to one of three treatment groups: subjects in Group 1 were given nicotine e-cigarettes, subjects in Group 2 were given nicotine patches, and subjects in Group 3 were given placebo e-cigarettes. The response variable was whether the subject maintained abstinence from cigarettes for six months, verified using exhaled breath carbon monoxide measurement.
(a) What type of experimental design is this?
(b) What is the response variable?
(c) What are the treatments? How many levels does the treatment have?
(d) Explain why it is not appropriate to use a one-way ANOVA to analyze the effectiveness of e-cigs with nicotine. Suggest an appropriate analysis.
(e) The results of the study are shown to the right. Using the procedure suggested in part (d), perform the analysis regarding the effectiveness of the treatment. Be sure to state the null and alternative hypotheses.