# LIR 832 Q_Exam_Answer_key_ Spring, 2004 - LIR 832...

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LIR 832 Qualifying Examination: Spring, 2004 This examination consists of 10 equally weighted questions which require basic knowledge of statistics. The examination lasts two hours, additional time will not be provided. Z and T tables are attached at the end of the examination. Partial credit is given only for arithmetic errors. Your work must be organized so that the grader can readily determine where the error occurred to obtain partial credit 1. We have taken a sample of our employees and calculated the time required to complete a standard task, the data from this study is provided in the following table. Calculate the sample mean and standard deviation of minutes to complete the task. ... Employee Minutes to complete task 19 21 4 38 46 51 2 61 1 ANSWER X X-Xbar (X-Xbar)^2 - 11 4 41 6 - 24 - 4 1 6 5 1 224 6 1 111 Mean(xbar) 10 8.400= Var(X) = SUM[(X-Xbar)^2]/n-1 2.898= Std(X) = sqrt(Var(X)) Mean = 10 Variance = 8.4 Standard Deviation = 2.898

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2. A simple random sample of 20 students at a high school yields a sample mean (combined) SAT score of 960 with a sample standard deviation of 100. Conduct a 10%, 5%, and 1% test of the alternative hypothesis that : 1000. ANSWER H A : : 1000 H O : : = 1000 t = If the absolute value of our t-statistic is greater than the critical t-value, we reject the null hypothesis.
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## This note was uploaded on 07/25/2008 for the course LIR 832 taught by Professor Belman during the Spring '07 term at Michigan State University.

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LIR 832 Q_Exam_Answer_key_ Spring, 2004 - LIR 832...

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