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Unformatted text preview: A and B are not independent. (c) P ( B  A ) = P ( A B ) P ( A ) = 2 4 3 4 = 2 3 . 5. (a) n = 7 and p = 0 . 4. (b) Let X denote how many of the 7 games the team wins. Assuming X has a binomial distribution, the required probability is P ( X = 4) = 7! 4!3! (0 . 4) 4 (1. 4) (74) = 0 . 19. 6. Hypotheses : H : = 1600 vs. H a : < 1600 Test statistic : t = x s/ n = 15701600 120 / 100 =2 . 5 . The df value is 1001 = 99. Pvalue : This is a leftsided test, so the Pvalue is the probability to the left of (below) the test statistic,2 . 5. Based on the t distribution with df = 99, the Pvalue is 0 . 007. Conclusion : Since Pvalue < . 05, there is sucient evidence to reject H . We conclude that the mean lifetime of all bulbs produced by the company is less than 1600 hours....
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 Spring '08
 TA
 Statistics

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