Mental practice tends to be most valuable after you have mastered a task at a basic level

One reason that adolescents report they generally feel happier when they are with their friends is that they

a. feel more "open" and accepted with friends than with parents. b. are able to "get away" with things their parents would not allow. c. spend less time with friends than with parents. d. none of the above.

In a one-factor between-subjects analysis of variance, the mean square for factor A is also

known as the _____ variance. a. within-groups b. between-groups c. common-groups d. independent-groups