Question

What sample size of U.S. adults do you need, if you would like to estimate the proportion of U.S. adults who are "pro-choice" with a 2.5% margin of error (at the 95% level)?

• 40
• 16
• 1,000
• 1,600

Your answer to the above question indicates that if you take a sample of that size, the sample proportion of adults who are pro-choice is:

• More than 2.5% away from the proportion who are pro-choice among all U.S. adults.
• Within 2.5% of the proportion who are pro-choice among all U.S. adults.
• Exactly equal to the proportion who are pro-choice among all U.S. adults.

If you were to use a random sample of size n = 640 U.S. adults (instead of what you found in question 1), what would the margin of error roughly be?

• 4%
• 0.156%
• 3%
• 5%

Answer 1