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Question: A consumer advocacy group wants to determine whether there is a difference between the proportions of the two leading automobile models that need major repairs (more than $500) within 2 years of their purchase. A sample of 400 two-year owner of model 1 is contacted, and a sample of 500 tow-year owners of model 2 is contacted. The numbers X1 and X2 of owners who report that their cars needed major repairs within the first 2 years are 53 and 78, respectively. Test the null hypothesis that no difference exists between the proportions in populations 1 and 2 needing major repairs against the alternative that a difference does exist. Use = .10

A consumer advocacy group wants to determine whether there is a difference between the proportions of the two leading automobile models that need major repairs (more than $500) within 2 years of their purchase. A sample of 400 two-year owner of model 1 is contacted, and a sample of 500 tow-year owners of model 2 is contacted. The numbers X1 and X2 of owners who report that their cars needed major repairs within the first 2 years are 53 and 78, respectively. Test the null hypothesis that no difference exists between the proportions in populations 1 and 2 needing major repairs against the alternative that a difference does exist. Use = .10