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Unformatted text preview: IE 121 – Spring 2003 Midterm exam 2 1. (20 points) In this problem, you need to select the correct answer. 1. Which of the following distributions is asymmetric? a) χ 2 distribution b) normal distribution c) t distribution 2. Suppose we want to test a goodness of fit to a normal distribution with mean equal to 12.5. The number of bins is chosen to be 8. What is the number of degrees of freedom that we have to use for the corresponding χ 2 test? a) 8 b) 6 c) 7 d) 5 3. The paired ttest has to be chosen over the pooled ttest if a) there is evidence for a strong positive correlation between pairs of observations b) the available sample size is small c) never – the pooled ttest is always better 4. The null hypothesis is H : σ 2 = σ 2 . Which test statistic has to be used for the hypothesis testing? a) z b) t c) χ 2 5. Suppose that we have found that, with the given sample size n 1 = n 2 = 300, the power of the test of the hypothesis H : p 1 = p 2 was found to be 0.15. We are interested in the (common for the two pop ulations) sample size required to to make the power of the test equal to 0.95. Which of the following can realistically be the right answer?...
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 Spring '08
 Perevalov
 Normal Distribution, Null hypothesis, Statistical hypothesis testing

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