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. would this be an example of an experiment or an observational study?