Pete pepsi wanted to see whether caffeine intake increased a subject's arousal state. he randomly assigned 100 high school seniors to either an experimental or control group. the experimental group drank a high caffeine soda, while control group drank a caffeine-free soda. he then measured and compared arousal states for both groups. no pre-test was used. what type of experimental design did pete use?

The correct answer is two group post-test only design.

Two group post-test only design refers to an experimental design that involves an experimental group that subject to treatment (in this case given a high caffeine dose), and a control group that is not given any treatment (no caffeine dosage in this example). This kind of study does not involve a pre-test (such as measuring arousal states prior to treatment). The only measurement is conducted on the two groups after they receive or do not receive treatment.