H6 - the adequacy of the model the bank records the...

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1 Economic Statistics Econ 321 Homework 6: due Tuesday June 29 Solve the following problems. Explain your logic and show your steps. 1. A manufacturer is testing a new model of a machine. The old model produced one hundred units per day with a standard deviation of ten. The manufacturer records the production levels with the new model in sixty-eight different days and finds that the sample variance is sixty-four. Can the manufacturer be ninety-nine percent sure that the new model is more reliable than the old one (lower variance) or is the result with the new machine in the confidence interval of the old model? 2. One hundred players toss a coin three times and the number of heads is recorded. The results are as follows: Heads 0 1 2 3 Frequency 19 28 11 22 Is this evidence enough to reject that the coin is fair? 3. An economist at the research department of a bank claims he has developed a model that can predict with a 95% certainty the number of housing mortgages that will end up in foreclosure in a given year. In order to test

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Unformatted text preview: the adequacy of the model the bank records the realized and the expected foreclosures in five different districts labeled A, B, C, D and E. The results are as follows: A B C D E Observed 33 75 57 85 33 Predicted 48 44 65 87 39 Does the evidence support the claim from the researcher? 4. A firm measured the following production levels in two of its plants labeled A and B: A 3.54 3.86 3.69 3.64 3.83 3.81 3.80 3.85 B 3.62 3.04 3.60 3.35 3.36 3.18 Based on this evidence can we conclude that both plants are equally reliable (same variance)? 2 5. A firm recorded the number of cars with defective breaks that were produced in a given month in each of its three plants labeled A, B and C. The results are as follows: A 33 25 41 38 33 28 B 43 33 44 47 41 37 45 C 43 45 38 39 52 Based on this evidence can we conclude that quality of all plants is the same (same means)?...
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This note was uploaded on 03/08/2011 for the course ECON 602 taught by Professor Chugh during the Spring '11 term at Johns Hopkins.

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H6 - the adequacy of the model the bank records the...

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