Question

1. In a​ poll, 69% of the people polled answered yes to the question​ "Are you in favor of the death penalty for a person convicted of​ murder?" The margin of error in the poll was 33​%, and the estimate was made with 94% confidence. At least how many people were​ surveyed?

2. A simple random sample of size n is drawn. The sample​ mean, x overbar, is found to be 17.9​,and the sample standard​ deviation, s, is found to be 4.9.

​(a) Construct a 95​% confidence interval about the mean if the sample​ size, n, is 35.

b) Construct a 95​% confidence interval about muμ if the sample​ size, n, is 51.

​(c) Construct a 99​% confidence interval about muμ if the sample​ size, n, is 35.

3. A doctor wants to estimate the mean HDL cholesterol of all​ 20- to​ 29-year-old females. How many subjects are needed to estimate the mean HDL cholesterol within 4 points with 99 % confidence assuming s=11.9 based on earlier​ studies? Suppose the doctor would be content with 90 % confidence. How does the decrease in confidence affect the sample size​ required?

Answer 1