Pregnant and breast-feeding women should eat at least 12 ounces of fish and seafood per week to ensure their babies’ optimal brain development, according to a coalition of top scientists from private groups and federal agencies. A nutritionist wants to know whether pregnant women are eating at least 12 ounces of fish per week. To do so, she obtains a list of the 340 members of a local chain of prenatal fitness clubs and mails a questionnaire to 60 of these women selected at random. Only 21 questionnaires are returned.
(a) What is the variable measured in this study?
(b) What is the population in this study?
(c) What is the sample from which information is actually obtained?
(d) What percentage of the women whom the nutritionist tried to contact responded?
(e) Is this an observational study or an experiment?