stats 363 HW-Section-9-6

# stats 363 HW-Section-9-6 - Section 9.6 Exercise 9.43. (a)...

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Section 9.6 Exercise 9.43 . ( a ) The hypotheses are H 0 : p 1 p 2 = 0 versus H a : p 1 p 2 < 0 : ( b ) This is a left-tailed test. ( c ) With n 1 = 140, n 2 = 140, x 1 = 74, x 2 = 81, the two individual sample proportions are b p 1 = 74 = 140 and b p 2 = 81 = 140, respectively, and the pooled sample proportion is b p = 74 + 81 140 + 140 = 155 280 = 31 56 : The test statistic is z = 74 140 81 140 r 31 56 25 56 1 140 + 1 140 ± = & 0 : 84 : This is a left-tailed test. At = 0 : z = 1 : 645 and the rejection region is z < 1 : 645. Since the test statistic z = & 0 : 84 is not in the rejection region, we cannot reject H 0 . There is insu±cient evidence to indicate that p 1 is smaller than p 2 . Exercise 9.45 . ( a ) The hypotheses are H 0 : p 1 p 2 = 0 versus H a : p 1 p 2 < 0 : With n 1 = 50, n 2 = 50, x 1 = 18, x 2 = 30, the two individual sample proportions are b p 1 = 18 = 50 = 0 : 36 and b p 2 = 30 = 50 = 0 : 60, respectively, and the pooled sample proportion is b p = 18 + 30

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## This note was uploaded on 04/20/2008 for the course MTH 1363 taught by Professor Cheng during the Spring '08 term at Creighton.

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stats 363 HW-Section-9-6 - Section 9.6 Exercise 9.43. (a)...

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