Obesity is generally defined as 30 or more pounds over a healthy weight. A recent study of

Question:

Obesity is generally defined as 30 or more pounds over a healthy weight. A recent study of obesity reports 27.5% of a random sample of 400 adults in the United States to be obese.
a. Use this sample information to compute the 90% confidence interval for the adult obesity rate in the United States.
b. Is it reasonable to conclude with 90% confidence that the adult obesity rate in the United States differs from 30%?