A Study Conducted by the National Center for Health Statistics

A study conducted by the National Center for Health Statistics as part of the Center for Disease Control and Prevention (CDC) found that, as of 2015-2016, 39.6% of Americans over the age of 20 fit the medical definition of being obese (BMI of 30 or higher) . A city known for its plentiful outdoor opportunities believes that number is lower among its residents. A representative sample of 80 city residents is collected and the BMI calculated for each (based on reported height and weight) . The variable of interest is whether the resident fit the medical definition of obese. The study found 22 people in the sample fit the medical definition of obese.
-Is a theory-based method appropriate for these data?

A) Yes, because a representative sample was collected.
B) Yes, because there were 22 people defined as obese and 58 people not defined as obese in the sample, and both of these values are greater than 10.
C) No, because the researcher did not collect a random sample.
D) No, because the national obesity rate is not 0.5.