An experiment investigating the effect of exercise on happiness randomly assigns participants to one of four groups : moderate aerobic exercise, strenuous aerobic exercise, moderate anaerobic exercise, strenuous anaerobic exercise. After one month, participants rate their happiness on a scale of 1 to 100 and the difference from their baseline score is recorded. Identify the response variable and the two factors.
- Response variable: happiness; factors: type of exercise, intensity of exercise
- Response variable: happiness; factors: moderate exercise, strenuous exercise
- Response variable:intensity of exercise; factors: happiness, type of exercise
- Response variable: happiness; factors: aerobic exercise, anaerobic exercise