Suppose you are conducting an impact evaluation using a posttest-only design with three groups: a control group, a group receiving treatment A, and a group receiving treatment B. The dependent variable is continuous, and sample is n=1,023, with participants approximately evenly divided between the three groups. What statistical test would be most appropriate for testing the null hypothesis of no difference between the three groups in the mean level of the outcome variable?

Suppose your agency has been evaluating an intervention using a one-group pretest-posttest design with 427 participants. The focal variable is continuous and, in looking at the boxplots, appears to be approximately bell-shaped. What statistical test would be most appropriate for testing the null hypothesis of no intervention effect (i.e., no change from before to after the intervention)?

Suppose that your agency has been evaluating an intervention using a posttest-only control group design. There were 155 people in the treatment group and 140 in the control group. The outcome variable is dichotomous. What statistical test would be most appropriate for testing the null hypothesis of no intervention effect?

Suppose that your agency has been evaluating an intervention using a posttest-only control group design.There were 95 people in the treatment group and 111 in the control group.The outcome variable takes the following three ordinal values: normal, overweight, and obese.What bivariate statistical test would be most appropriate for testing the null hypothesis of no intervention effect?