Question

Part A

An automotive manufacturer wants to know the proportion of new car buyers who prefer foreign cars over domestic.

Step 2 of 2: Suppose a sample of 1269 new car buyers is drawn. Of those sampled, 914 preferred domestic rather than foreign cars. Using the data, construct the 90% confidence interval for the population proportion of new car buyers who prefer foreign cars over domestic cars. Round your answers to three decimal places.

Part B

The mean number of hours watching TV per week for a sample of 295 teenagers is 22. If the margin of error for the population mean with a 95% confidence interval is 1.9, construct a 95% confidence interval for the mean number of hours watching TV per week for all teenagers.

Answer 1

Part A

(0.700, 0.741)

Observed
0.7203	p (as decimal)
914/1269	p (as fraction)
914.	X
1269	n
0.014	std. error
0.700	confidence interval 90.% lower
0.741	confidence interval 90.% upper
0.021	margin of error

Part B

(-1.825, 1.975)