A researcher measured condom use at a university that introduced a safer sex promotion program, and at another university that did not introduce this program. She measured condom use once before and once after the program was introduced. What kind of design is this? Question 54 options: Nonequivalent control group pretest-posttest design Nonequivalent control group posttest only design Interrupted time series design Nonequivalent control group time-series design In a 2 4 factorial design, ____ main effect(s) are possible. Question 55 options: 2 4 1 3 8