A random sample of 1500 residential telephones in Phoenix foundthat 385 of the numbers were unlisted. A random sample in the sameyear of 1200 telephones in Scottsdale found that 311 wereunlisted.
Round your answers to four decimal places (e.g. 98.7654).
(a) Calculate a 95% two-sided confidence interval on the differencein the proportions of unlisted numbers between the twocities.
Enter your answer; 95% confidence interval, lower bound ≤p1-p2≤Enter your answer; 95% confidence interval, upper bound
(b) Is there a significant difference between the two proportionsat α = 0.05? Choose your answer in accordance to the itemb) of the question statement                                       No.Yes.
(c) Calculate a 90% two-sided confidence interval on the differencein the proportions of unlisted numbers between the twocities.
Enter your answer; 90% confidence interval, lower bound ≤p1-p2≤Enter your answer; 90% confidence interval, upper bound
