4 Questions for the Statistics for Business I

2

HARDMAN

DSC 210

Take-Home Questions for the Final Exam

Tues, Dec 15, 2017

(15 points)

1. A sample of 120 students yielded a sample mean GPA of 3.35, and a sample standard deviation equal to 0.28. Calculate the 98% confidence interval for the population mean GPA. (5 points) SHOW YOUR WORK!

2. In a sample of 125 statistics students, 35 said that finding confidence intervals for population proportions was their favorite topic. Give the 99% confidence interval estimate of the population proportion of statistics students whose favorite topic is finding confidence intervals for p. (5 points) SHOW YOUR WORK!

3. What effect does increasing the sample size have on the length of a CI?

EXPLAIN YOUR ANSWER (2 points)

4. Find the value of the Z-critical number that you would use to construct a 75% CI for . SHOW YOUR WORK! Just the number will earn exactly 0 points, even if it is the correct number! (3 points)