3. Recent information suggests that obesity is an increasing problem in America among all age groups. Aiming to show that no more than 30% of adult Americans are obese, a study found that 963 individuals in a sample of 3325 adults are obese (a body mass index exceeding 30; this BMI index is a measure of weight relative to height). a.) Construct a 90% confidence interval for the population proportion of obesity. b.) Does the study provide enough support to its goal, at a 5% significance level? c.) If someone is designing a follow-up study for the same goal, but at a 1% significance level. Can you help him to decide the minimal sample size needed (so that he knows how much budget is needed)? [State any assumption(s) if needed]