The American Academy of Pediatrics advises against feeding babies solid foods before they reach 4months old. A research group obtains a simple random sample of 5,000 mothers nationwide andmails each one a survey asking questions about their feeding practices. Of the 1,000 mothers whocompleted the survey and mailed it back, 40% indicated that they started feeding their baby solidfoods before age 4 months. A newspaper reports on the study with the headline, "Infants are FedSolid Foods Too Soon." Which of the following is the most serious concern regarding this study?