California and New York lead the list of average teachers’ salaries. The California yearly average is $64,421 while teachers in New York make average annual salaries of $62,332. Random samples of 45 teachers from each state yielded the following.
California: Sample Mean= 64,510; Population standard deviation = 8200
New York: Sample Mean= 62900; Population standard deviation = 7800
2) A real estate agent compares the selling prices of randomly selected homes in two municipalities in southern Pennsylvania to see if there is a difference. The results of the study are shown. Is there enough evidence to reject the claim that the average cost of a home in both locations is the same? Use =0.05.
3) The average monthly Social Security benefit for a specific year for retired workers was $954.90 and for disabled workers was $894.10. Researchers used data from the Social Security records to test the claim that the difference in monthly benefits between two groups was greater than $30. Based on the following information, can the researchers’ claim be supported at the 0.05 level of significance?
4) The average credit card debt for a recent year was $9205. Five years earlier the average credit card debt was $6618. Assume the sample sizes of 35 were used and the population deviations of both samples were $1928. Find the 95% confidence interval of the difference in means.
5) The mean travel time to work for Americans is 25.3 minutes. An employment agency wanted to test the mean commuting times for college graduates and those with only some college. Thirty-five college graduates spent a mean time of 40.5 minutes to work with a population variance of 67.24. Thirty workers who had completed some college had a mean commuting time of 34.8 minutes with a population variance of 39.69. At the 0.05 level of significance, can a difference in means be concluded?
6) A random sample of non-English majors at a selected college was used in a study to see if the student retained more from reading a 19th-century novel or by watching DVD form. Each student was assigned one novel to read and a different one to watch, and then they were given a 100-point written quiz on each novel. The test results are shown. At = 0.05, can it be concluded that the book scores are higher than the DVD scores?