The Journal of Genetic Counseling compiled statistics on thousands of births over a long period of time, and reported that otherwise healthy first cousins are at no great risk of passing chance birth defects onto their children: "normal" parents have a 3 to 4% chance of bearing a child with a serious birth defect, compared to a 5 to 7% chance for first cousins.
a. Sample percentages were presumably at the center of each reported range. Report the sample percentage of birth defects for "normal" parents and for first cousins.
b. For which group did they apparently have a larger sample size-"normal" parents or first cousins? Explain.