The normal probability function is called a two-parameter function because all normal curves differ from one another only in mean and variance, all other moments about their means being zero.

According to research on friendship during middle childhood,

A) by age 8 or 9, children name only a handful of good friends. B) friendships are highly unstable over the elementary and middle school years. C) school-age children's friendships are less selective than those of preschoolers. D) friendships are largely based on engaging in similar activities.

Which qualities best describe collectivism?

a. ?interdependence, cooperation, and lack of conflict b. ?independence and self-reliance c. ?personal achievement d. ?uniqueness