(Use this problem for questions 16-20.) In a recent market research report, based upon responses from 5,000 randomly-chosen recent college graduates working in Washington, DC, the average starting salaries for college graduates employed in Washington, DC, is $45,000 with a standard deviation of $7,500. (Each question here is worth two points.)
16. With a 68% confidence level, what is the range of starting salaries in Washington, DC for recent college graduates? Show your work.
17. With a 95% confidence level, what is the range of starting salaries in Washington, DC for recent college graduates? Show your work.
18. With a 99% confidence level, what is the range of starting salaries in Washington, DC for recent college graduates? Show your work.
19. At a significance level of 5%, what is the confidence interval of starting salaries in Washington, DC for recent college graduates? Show Your Work.
20. If the market research firm had chosen to use only 500 random responses (instead of 5,000) to calculate average starting salaries for recent college graduates working in Washington, DC, how would this affect the confidence interval results from Question 19?
a. It would narrow
b. It would expand (reducing sample size reduces precision, increases CI)
c. It would not change