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In 2008, a small dealership leased 21 Subaru Outbacks on 2-year leases. When the cars were returned in 2010, the mileage was recorded (see below). 40.003 24.945 14.321 17.344 44.760 44.528 20.252 33.323 24.203 41,787 58.352 35.826 25714 28.927 25,005 43.319 23.951 43.562 53.633 31.858 36.755 Click here for the Excel Data File (a) is the dealer's mean significantly greater than the national average of 30,205 miles for 2-year leases? Using the 10 percent level of significance, choose the appropriate hypothesis. a. Ho: US 30,205 miles vs. H1: U> 30,205 miles, reject Ho if tcalc > 1.3250 b. Ho: 2 30.205 miles vs. HiU> 30,205 miles, reject Ho if tcalc> 1.3250 C. Ho: US 30,205 miles vs. H1: U< 30,205 miles, reject Ho iftcalc > 1.3250 d. HUS 30,205 miles vs. Ho: U> 30,205 miles, reject Ho if tcalc > 1.3250 (b)Calculate the test statistic. (Round your answer to 2 decimal places.) Test statistic (c)The dealer's cars show a significantly greater mean number of miles than the national average at the 10 percent level.

yes

no

Answer 1

mean x ) = 712368 33422.985) 21 mean (K) = Ex - Tag - 1992-837 Sample Sonderd duinhan (3) = 5Elx-)* n-l (140003 - 33922-1857)+--+36755-33922.2857) 91-1 2803836590-9857 20 - 5140991829.51439 S = [118-10.84317 Hoil < 30205 Haide > 30905 (one failed test) n = 91, = 33922.2857, 5=11840.9631, 010 test Statistic, 33922:2857-30205 1:4387 **505 = 1840-9631 | JOT

critical value Critical value 1 2 3 = -th- 21-1 -20 2=0.10. ta, df = +010,20= + 1-3950 (using t table] Since, test. Stadistic value is greater than the critical value So, lur Reject the Ho O 11 Conclusion ! There is a sufficient evidence to support the claim at x = 0.10 level of signifionce (c) yes, because text statistic is greater than the critical value.