Question 1

What is the relationship between the confidence interval and the margin of error?

Question 1 options:

	The confidence interval is half the width of the margin of error.
	The margin of error is twice the confidence interval.
	None of these
	The confidence interval is twice the margin of error.

Question 3

Question 3 options:

A researcher is interested in estimating the how recent college graduates are using their degree in their current profession. In a random sample of 800 recent college graduates 280 report, they are not using degree with their current job. Compute a 90% confidence interval for the true proportion of recent college graduates that are not using their degrees in their jobs. Round to 3 decimal places.

Lower limit =

Upper limit =

Question 4

Write a summary statement for this confidence interval. Be sure to use the context of the problem.

Question 5

A community college would like to estimate the percentage of their students that have children under 18 years old. They randomly select 450 students and ask them about having children and their children's ages. The 90% confidence interval for this situationis (24.5%, 31.5%)

Which statement below correctly summarizes the confidence interval?

	Thechance a student will have children (
	We are 90%confident that the percentage of all students at this community college that have children (
	There is a 90% chance that the percentage of students at this college that have children (
	We are 90%confident that the percentage of all students at this community collegethat have children (

Question 6

A pollster wishes to estimate the true proportion of U.S. voters who oppose capital punishment. How many voters should be surveyed in order to be 90% confident that the true proportion is estimated to within 3.5%?

Question 7

The confidence interval at the 95% level of confidence for the true population proportion was reported to be (0.284, 0.416). Which of the following is a possible 90% confidence interval from the same sample?

	(0.295, 0.405)
	(0.263, 0.437)
	(0.679, 0.821)
	(0.315, 0.425)

Question 9

Write a summary statement for your confidence interval in question #1.

Question 12

A company wants to estimate the mean lifetime of their D-batteries. They randomly select 50 D-batteries and measure how long they last in a flashlight. Use the data below to compute a 99% confidence interval for the mean lifetime of the company's D-batteries.

Round your answers to 2 decimal places.

Time (hours) 31.3 39.6 39.2 34.8 42.9 33.9 35.2 35.3 35.1 31.3 37.1 39.2 38.1 40.7 29 39.1 29.7 44.2 33.4 32.1 31.6 32.6 32.9 31.5 36.9 41.7 37.3 34.1 36 37.8 34.5 33.6 39.9 39.6 34.4 32.2 34.9 32.6 36.1 36.1 35.2 39.8 35.3 31.5 30 33.3 34.1 38.7 36.5 42.4