Econ 210 Winter 2008 Practice Questions Midterm IIa_1

# Econ 210 Winter 2008 Practice Questions Midterm IIa_1 -...

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Practice Questions IIa 1. Assume you are sampling from a Normal Distribution with unknown mean and variance. a) You draw a sample of size 10 and calculate a sample mean of 33 and a sample variance of 225. Test the Null Hypothesis that the true mean of the distribution is equal to 22 and report the p-value. Also report if you can reject the null hypothesis at a 10%, 5%, 1% level. b) Why is the above test not valid if the underlying distribution is not known? 2. Assume you sample from Chi-square Distribution (mean K, variance 2K) a) What is the mean and variance of the sample mean? a) Assume a sample size of N=100. What is the probability that the sample mean is
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Unformatted text preview: greater than 100? What is the probability that the sample mean is negative? 3. Random variable X~(5,10000) follows an Erlang distribution. A friend of yours takes a sample of 100 observations anyway, calculates the sample mean of 24.6 and maintains that ( 29 24.6 P X < =.975. Comment on your friend’s statement. 4. Assume you give a test to 100 individuals and calculate a sample mean score of 120 and a sample variance of scores of 10000. Test the hypothesis that the true population mean equals 100. Report t-stat, p-value and if your null hypothesis can be rejected at the usual levels....
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