In the article "Food Allergy Advice May Be Peanuts" (Science News, Vol. 174, No. 12, pp. 8-9), N. Seppa reports that early exposure to peanuts seems to lessen the risk of nut allergy. Of 4000 Jewish children sampled in Britain, 1.85% had peanut allergies; and of 4600 Jewish children sampled in Israel, where early peanut consumption is more common, 0.17% had peanut allergies. The researcher chose Jewish children in both countries to limit genetic differences between groups.
a. Is this study descriptive or inferential?
b. Is this study observational or experimental?