A group of adolescents developed a new game. After school they all climb aboard a freight train, and when it crosses the river, they dive off the top of the box cars into the water. This dangerous behavior is best explained by which of Elkind's concepts?

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