Identical twins reared apart. Because they share an identical genotype, twins make i...

Identical twins reared apart. Because they share an identical genotype, twins make ideal subjects for investigating the degree to which various environmental conditions affect personality. The classical method of studying this phenomenon, and the subject of a book by Susan Farber (Identical Twins Reared Apart, New York: Basic Books, 1981), is the study of identical twins separated early in life and reared apart. Much of Farber’s discussion focuses on a comparison of IQ scores. The data for this analysis appear in the accompanying table. One member (A) of each of the n = 32 pairs of twins was reared by a natural parent; the other member (B) was reared by a relative or some other person.

a. Is there a significant difference between the average IQ scores of identical twins when one member of the pair is reared by the natural parents and the other member of the pair is not? Use α = .05 to draw your conclusion.