The national longitudinal study on adolescent health of more than 12,000 adolescents found that those who had dramatically higher rates of smoking, drinking, using marijuana, getting into fights, and initiating sexual activity.

Na test of the effects of sleep deprivation on problem-solving skills, research participants are allowed to sleep either 4 or 8 hours on each of three consecutive nights. this research is an example of: a)naturalistic observation. b)survey research. c)a case study. d)an experiment. e)correlational research.