chapter 1

Chapter 9: Inferences Based on Two Samples28. We will test the hypotheses: µ − µ 10H0:1 2= vs. Ha: µ1− µ2> 10x − y −104.5= = 2.08222.75 4.44+ 2.17( )statistic is t =The degrees of freedom( )10 522 22.75 4.44(10+5)=2 22 22.75 4.44( ) ( ). The test22.08ν == 5.59 ≈ 6 and the p-value from table A.8 is approx .04,3.95105+9 4which is < .10 so we reject H 0 and conclude that the true average lean angle for older femalesis more than 10 degrees smaller than that of younger females.29. Let µ1= the true average compression strength for strawberry drink and let µ2= the trueaverage compression strength for cola. A lower tailed test is appropriate. We testH µ − µ 0 vs. H µ − µ 00:1 2=a:1 2