Rank these designs in order of level of internal validity, from lowest to highest: (a) pre-experimental design (b) true experimental design (c) quasi-experimental design What is the difference between...

Rank these designs in order of level of internal validity, from lowest to highest:

(a) pre-experimental design

(b) true experimental design

(c) quasi-experimental design

What is the difference between a nonequivalent control group design and a pretest posttest control group design?