What is a research design called when neither the participant nor the experimenter observing the participant knows which participants were given an active substance and which were given a placebo?

Hui is discussing encouraging trends in U.S. teenage sexuality. Which is NOT a 2015 statistic that he can mention?

A) U.S. teen birth rates are lower than in Europe. B) Most sexually active teens say they used contraception during their last intercourse. C) Fewer teens report having sex. D) Most teens have sex within a committed relationship.

Hardy people (those unusually resistant to the effects of stress) are characterized by a(n)

a. sense of personal commitment to self, work, and family. b. feeling of no control over their lives. c. attitude of just going with the flow. d. tendency to avoid extra responsibilities.