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Unformatted text preview: Stat312: Midterm Exam II. Moo K. Chung, Yulin Zhang [email protected], [email protected] November 11, 2004 Please use the following R output in answering the appropriate exam problems. > pnorm(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6)) [1] 0.84 0.86 0.88 0.90 0.92 0.93 0.95 > pt(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6),9) [1] 0.83 0.85 0.87 0.89 0.90 0.92 0.93 > pt(c(1.0,1.1,1.2,1.3,1.4,1.5,1.6),10) [1] 0.83 0.85 0.87 0.89 0.90 0.92 0.93 1. A mixture of pulverized fuel ash and Portland ce ment should have a compressive strength of more than 1000KN/m 3 . The mixture will not be used unless experimental evidence indicates that the strength specification has been met. Suppose com pressive strength for specimens of this mixture is normally distributed with σ 2 = 98 2 . The sample mean of compressive strength for 10 specimens is ¯ x = 1050 . (1) What are the appropriate null and alternate hy pothesis (5 points)? (2) What would be the appropriate test statistic for the hypothesis testing? What is the probability dis tribution of your test statistic when H is true? (5 points each) (3) Do hypothesis testing at 85% level. Has thelevel....
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 Fall '04
 Chung
 Statistics, Normal Distribution, Null hypothesis, Statistical hypothesis testing, CHD

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