1. Dylan wants to determine a 99 percent confidence interval for the true proportion of high school students in the area who attend their home basketball games. How large of a sample must he have to get a margin of error less than 0.04? [To find n, use the value p^ = 1/2 for the sample proportion and the values for z* from Table C.]
[Round to the smallest integer that works.] n =______
2. Over half of all American teens (ages 12 to 17 years) have an online profile, mainly on Facebook. A random sample of 524 teens with profiles found that 335 included photos of themselves.
Give the 99.9% large-sample confidence interval for the proportion p of all teens with profiles who include photos of themselves.
Large-sample Interval: _______ to _______
3. 2.5758An automobile manufacturer would like to know what proportion of its customers are not satisfied with the service provided by the local dealer. The customer relations department will survey a random sample of customers and compute a 99% confidence interval for the proportion who are not satisfied.
(a) Past studies suggest that this proportion will be about 0.27. Find the sample size needed if the margin of the error of the confidence interval is to be about 0.01.
(You will need a critical value accurate to at least 4 decimal places.)
Sample size: _____
(b) Using the sample size above, when the sample is actually contacted, 32% of the sample say they are not satisfied. What is the margin of the error of the confidence interval?
MoE:____