Question

1. Public health researchers in want to estimate the proportion of residents classified as obese in the county. In a study of 400 residents of the county, 129 were classified as obese. What is the margin of error for a 99% confidence interval for p, the true proportion of residents that are obese according to this classification. Give you answer to 3 decimal places.

2. In a sample of 110 US residents, 46 said that they had approved of the job the president is doing. Let p be the true proportion of US residents that approve of the presidents job performance, and calculate the standard error of p ^. Give your answer to 3 decimal places, don't round until the the calculation is complete.

Answer 1

1) margin of error = 0.060

2) standard error = 0.047