Chapter 10 Exercises
10.40 A sample of high school seniors showed that 18 of 60 who owned PlayStation 3 spent more than an hour a day playing games, compared with 32 of 80 who owned Xbox 360. Is there a significant difference in the population proportions at α = .10?
10.47 Has the cost to outsource a standard employee background check changed from 2005 to 2006? A random sample of 10 companies in spring 2005 showed a sample average of $105 with a sample standard deviation equal to $32. A random sample of 10 different companies in spring 2006 resulted in a sample average of $75 with a sample standard deviation equal to $45. (a) Conduct a hypothesis test to test the difference in sample means with a level of significance equal to .05. Assume the population variances are not equal. (b) Discuss why a paired sample design might have made more sense in this case.
10.58 A ski company in Vail owns two ski shops, one on the west side and one on the east side of Vail. Ski hat sales data (in dollars) for a random sample of 5 Saturdays during the 2004 season showed the
following results. Is there a significant difference in sales dollars of hats between the west side and east side stores at the 5 percent level of significance? (a) State the hypotheses. (b) State the decision
rule and sketch it. (c) Find the test statistic and state your conclusion.
Saturday Sales Data ($) for Ski Hats
Saturday East Side Shop West Side Shop
1 548 523
2 493 721
3 609 695
4 567 510
5 432 532
The solution provides step by step method for the calculation of testing of hypothesis. Formula for the calculation and Interpretations of the results are also included. Interactive excel sheet is included. The user can edit the inputs and obtain the complete results for a new set of data.