Question

To design a new advertising campaign, Ford Motor Company would like to estimate the proportion of drivers of the new Ford Fusion that are women. In a random sample of 95 Fusion owners, 45 of them were women. What is the 90% confidence interval estimating the proportion of all drivers who are women?

options:

1) ( 0.38942 , 0.55795 )

2) ( -0.38942 , 0.55795 )

3) ( 0.44205 , 0.61058 )

4) ( 0.42246 , 0.52491 )

5) ( 0.40803 , 0.53934 )

Answer 1

sample proportion = (number of woman)/(total number) = 45/95

z score for 90% confidence interval is z critical = 1.645

sample size n = 95

Formula for confidence interval is

placing the values in formula

Therefore, option A is the correct answer for 90% confidence interval