1. An experiment tests the effects of new devices to help stop smoking. They tested hypnosis, nicotine gum, nicotine patch, and nicotine inhaler. They believed the effects may differ for men and women, so men and women were randomized to the treatments separately. 25 subjects are randomized into each treatment combination. They obtained an F statistic for interaction of 84.85 with a P-value less than 0.001. What conclusion can they make?

A. Males quit more often than females.
B. The devices differed in their ability to help people quit smoking.
C. Genders differed in their responses to the devices.

2. A study of cardiovascular risk factors compared heavy smokers, light smokers, and nonsmokers. Both men and women were included in the study and gender differences were also to be investigated. One of the variables measured was the heart rate after six minutes of exercise.

The two factors being studied in this experiment are

A. men and women.
B. heart rate and smoking level.
C. gender and smoking level.

3. A study of cardiovascular risk factors compared heavy smokers, light smokers, and nonsmokers. Both men and women were included in the study so that the two factors are smoking level and gender. There were 25 subjects included in each of the combinations of gender and smoking status. One of the variables measured was the heart rate after six minutes of exercise. A two-way ANOVA is performed with the partial ANOVA table given below.

Analysis of variance for heart rate

The P-value for the F test for the main effect of smoking is

A. less than 0.001.
B. between 0.001 and 0.010.
C. greater than 0.10.