Answer the following statement(s) true (T) or false (F)

1. In ex post facto control group designs, comparison groups are assigned prior to treatment.
2. Time order cannot be assured in nonequivalent control group designs.
3. Internal validity in experiments is weakened by noncomparability of groups.
4. Maturation in experiments occurs when changes in outcome scores are likely due to a length treatment period.
5. Although cross-population generalizability is difficult to achieve using experiments, a true experiment usually has high sample generalizability.

1. False
2. True
3. True
4. False
5. False