What do developmentalists call the average performance of a large sample of children of a given age?

According to Seligman and Peterson, the human strength of "justice" is expressed by the positive traits of

a. love, kindness, and social intelligence. b. persistence, integrity, and vitality. c. fairness, leadership, and citizenship. d. forgiveness, humility, prudence, and self-control.

An appropriate correlation coefficient describing the relationship between two artificially dichotomous variables is

a. biserial correlation. b. phi coefficient. c. tetrachoric correlation. d. point biserial correlation.