Mark was pretty aggressive when he was in his early twenties. At the drop of a hat he became angry and was quick to act violently. Now Mark is 60 years old and is much calmer than he was back then. Mark's levels of the hormone have .

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a.static group comparisonb. pretest-posttest control group designc.control-group-time-series designd. nonrandomized control-group pretest-posttest design