This document provides solutions for two-sample hypothesis testing problems.
Andrew Taylor
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Due by 11.59pmJuly 20th1Chapter 10Two-Sample Hypothesis TestsAssignmentPlease providedetailed solutions to the following problems/exercises (4problems/exercises x8pointseach):1) Discover Card would like to test the hypothesis that the average credit score for an adult in Dallas isdifferent from the average credit score for an adult in Houston. A random sample of 40 adults in Dallashad an average credit score of 699 and a random sample of 35 adults in Houston had an average creditscore of 682. It is believed that the population standard deviation for credit scores is 44 and 41 for Dallasand Houston residents, respectively. Discover Card would like to setฮฑ= 0.05. Define Population 1 asDallas and Population 2 as Houston and use the critical value approach to test this hypothesis.Null Hypothesis:๐ป0:ฮผ1โฮผ2=0Alternative Hypothesis:๐ปเฏ:ฮผ1โฮผ2โ 0Type of test:Z test for two population mean(two tailed) assumingequal variance.Test Statistic:Pooled variance(๐2)=(๐1โ1)โ๐12+(๐2โ1)โ๐22๐1+๐2โ2=39โ442+34โ41240+35โ2=1817.232877Test Statistic =๐เดค1โ๐เดค2เถง๐2โแ1๐1+1๐2แ=699โ682เถง1817.232877โแ140+135แ=1.7230Rejection region:As this is a two tailed test so thecritical value is Z(0.025) = 1.96The rejection region is,|Test Statistic| > Critical value = 1.96Conclusion:The test statistic is not falling in the rejection region thus we arefailing torejectthe null hypothesis.Conclusion isthere is not a significant difference between theaverage credit score for an adult in DallasandHouston.2) Auto Trader Group (ATG) would like to test the hypothesis that the average age of an imported car onthe road is greater than the average age of a domestic car. The following data shows the sample size andthe average age of cars for import and domestic cars along with the population standard deviations.DomesticImport
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