11.39 Exercise and education programs: Irwin and colleagues (2004) conducted research on adherence to an exercise regimen. Participants were asked to attend a monthly group education program to help them change their exercise behavior. Participants were divided into three categories: those who attended fewer than 5 sessions, those who attended between 5 and 8 sessions, and those who attended between 9 and 12 sessions. The researchers assessed the number of minutes of exercise per week for all participants. Here are the data: <5 sessions: 155, 120, 130 5–8 sessions: 199, 160, 184 9–12 sessions: 230, 214, 195, 209

a. What is the independent variable in this study? What are its levels?

b. What is the dependent variable in this study?

c. Use the six steps of hypothesis testing to conduct a oneway between-groups ANOVA.

d. What is R2 for these data? How large is this effect according to Cohen’s conventions?

e. What is ω 2 for these data? How large is this effect according to Cohen’s conventions?