### Free Educational Resources

• > IN A STUDY OF THE INCOME OF U.S. FACTORY WORKER...
+

# IN A STUDY OF THE INCOME OF U.S. FACTORY WORKERS, A RANDOM SAMPLE

##### Rating:
(0)
Author: Christine Farr
##### Description:

http://theperfecthomework.com/in-a-study-of-the-income-of-u-s-factory-workers-a-random-sample-of-100-workers-shows-a-sample-mean-of-35-000/

1. In a study of the income of U.S. factory workers, a random sample of 100 workers shows a sample mean of \$35,000. Assume that the population standard deviation is \$4,500, and that the population is normally distributed.
A) Compute the 90%, and 99% confidence intervals for the  unknown population mean.
B) Briefly discuss what happens to the width of the interval estimate as the confidence level increases. Why does this seem reasonable?
2. In a study of the starting salary of college graduates with degrees in Accounting, a random sample of 40 graduates shows a sample mean of \$36,000 and a sample standard deviation of \$2,500. Assume that the population is normally distributed.
A) Compute and explain a 95% confidence interval estimate of the population mean starting salary for Accounting graduates.

3. A telephone poll of 900 American adults asked "where would you rather go in your spare time?"  One response, by 250 adults, was "a movie". Compute and explain a 95% confidence interval estimate of the proportion of all American adults who would respond "a movie".

(more)
##### Try a College Course Free

Sophia’s self-paced online courses are a great way to save time and money as you earn credits eligible for transfer to over 2,000 colleges and universities.*

No credit card required

25 Sophia partners guarantee credit transfer.

226 Institutions have accepted or given pre-approval for credit transfer.

* The American Council on Education's College Credit Recommendation Service (ACE Credit®) has evaluated and recommended college credit for 21 of Sophia’s online courses. More than 2,000 colleges and universities consider ACE CREDIT recommendations in determining the applicability to their course and degree programs.

Tutorial