Question

If, based on a sample size of 950, a political candidate finds that 514 people would vote for him in a two-person race, what is the 90% confidence interval for his expected proportion of the vote? Would he be confident of winning based on this poll? | || A 90% confidence interval for his expected proportion of the vote is || (Use ascending order. Round to four decimal places as needed.)

Answer 1

Answer Date: 09/02/2020 A 90% confidence interval for the proportion of vote is, First, compute proportion, the z-critical value then find confidence interval. The proportion is, P= _514 950 = 0.5411 The z-critical value is, From the standard normal table, the z-critical value at 90% confidence is 1.645.

90%C.I. = p zcx n 10.5411(1-0.5411) = 0.5411+ 950 = 0.5145 to 0.5677 A 90% confidence interval for the proportion of vote is 0.5145 to 0.5677).