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prof
Posts:
5
Registered:
7/10/06


hypothesis test question on two proportions
Posted:
Jul 10, 2006 5:29 PM


In the two population proportion test of H0: p1 = p2 vs Ha: p1 not equal p2 with a los of 0.05, one way to conduct the test is to construct a 95% CI on p1  p2. Then, if the interval contains "0", accept H0; otherwise reject H0. An alternate way is to calculate the z statistic under the assumption that H0 is true and compare to the 5% critical region. If the statistic is in the critical region, reject H0; otherwise accept H0. The question is: do the two methods give identical conclusions? The answer is not obvious to me since in the CI approach an assumption of H0 being true is not used; thus there are separate estimates for the two sample proportions which appear in the CI formula. whereas, in the test statistic approach, H0 being true is assumed; thus giving a combined estimate for the common proportion p which is used in the test statistic.. It is not obvious that identical conclusions would always be reached. Help please!!!



