xam2 Online Portion Overview 1 2 3 4 5 6 7 8 9 10 1 of 20 co

xam2 Online Portion Overview 1 2 3 4 5 6 7 8 9 10 1 of 20 complete This Test 40 pts This Question 2 pts Before spending huge sums to advertise to car owners that they shou fill their tires with nitrogen, would be wise a survey to determine the percentage of car owners who would pay for the nitrogen. How many randomly selected car should be that we want to be 95% confident that the sample percentage is within five percentage points of the true percentage of all car owners who would be willing to pay for the nitrogen. n L (Round up to the nearest integer.) Enter your answer in the answer box. Submit Test Previous Question Next Question m200 quiz05.pdf m200 quiz05 doc

Solution

We use p=0.5 as estimated.

Given a=1-0.95=0.05, Z(0.025) = 1.96 (from standard normal table)

So n=(Z/E)^2*p*(1-p)

=(1.96/0.05)^2*0.5*0.5

=384.16

Take n=385