Jorge studies the effects of mnemonic training on learning vocabulary. He randomly assigns half of the students to a no treatment control group and assigns the others to a mnemonic training group. He assesses students at the end of the study and compares how many words they know. Which of the following designs is Jorge best illustrating?
◦ Pretest-posttest control group design
◦ Posttest-only control group design
◦ Time series design
◦ Nonequivalent group control group design