Dr. Pete Moss uses the twin-study method and finds a correlation of +.50 on self-esteem for MZ twins, but only a +.30 correlation for DZ twins. What conclusion might be drawn from these results?

From the positive correlation derived from both samples, which were MZ (monozygotic) or identical twins and DZ (dizygotic) or fraternal twins, we can conclude that twins tend to share the same self-esteem levels. However, from the differences in the correlation power, we can say that identical twins tend to share the same self-esteem levels (r = 0.50) more often than fraternal twins (r = 0.30).