A 7 yr old medical research study reported that woman whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were woman whose mothers did not take the drug.

a. This study involved comparison of two populations. What were the populations?
b. Do you suppose the data were obtained in a survey or experiment?
c. For the population of woman whose mother took the drug DES during pregnancy, a sample of 3980 woman showed that 63 developed tissue abnormatly that could lead to cancer. Provide a descriptive statistic that could beused to estimate the number of women out of 1000 in this population who have tissue abnormalities.
d. For the population of women wose mother did not take the drug during pregnancy, what is the estiimate of the number of woman out of 1000 who would be expected to have tissue abnornalities?
e. Medical sudies often use a relatively large sample (in this case 3980). Why?