EC315_HW2_Jamie_Boyer

EC315_HW2_Jamie_Boyer - Quantitative Research Methods Jamie...

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Quantitative Research Methods Jamie Boyer Week 2 Chapter 6 36. An investment will be worth $1000, $2000, or $5000 at the end of the year. The probabilities of these values are .25, .60, and .15, respectively. Determine the mean and variance of the worth of the investment. Let X be the investment worth. The mean is: E(X) = 1000 * 0.25 + 2000 * 0.60 + 5000 * 0.15 = 2200 the variance is: Var(X) = 1000^2 * 0.25 + 2000^2 * 0.60 + 5000^2 * 0.15 - 2200^2 Var(X) = 1560000 39. A Tamiami shearing machine is producing 10% defective pieces, which is abnormally high. The quality control engineer has been checking the output by almost continuous sampling since the abnormal condition began. What is the probability that in a sample of 10 pieces: a. Exactly 5 will be defective? 10. choose 5 * 0.1^5 * 0.9^5 = 252 * 0.1^5 * 0.9^5 = 0.0014880348 b. 5 or more will be defective? 10 choose 5 * 0.1^5 * 0.9^5 + 10 choose 6 * 0.1^6 * 0.9^4 + 10 choose 7 * 0.1^7 * 0.9^3 + 10 choose 8 * 0.1^8 * 0.9^2 + 10 choose 9 * 0.1^9 * 0.9^1 + 10 choose 10 *
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EC315_HW2_Jamie_Boyer - Quantitative Research Methods Jamie...

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