PracticeExamNumber2

PracticeExamNumber2 - A researcher was investigating...

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A researcher was investigating possible explanations for deaths in traffic accidents. He examined data from 1991 for each of the 50 states plus the District of Columbia. The data included the number of deaths in traffic accidents (labeled as the variable Deaths), the average income per family (labeled as the variable Income), and the number of children (in multiples of 100,000) between the ages of 1 and 14 in the state (labeled as the variable Children). As part of his investigation he ran the following multiple regression model Deaths = E 0 + 1 (Children) + 2 (Income) + H i where the deviations i were assumed to be independent and normally distributed with mean 0 and standard deviation V . This model was fit to the data using the method of least squares. The following results were obtained from statistical software. Source df Sum of Squares Model 2 48362278 Error 48 3042063 Variable Parameter Est. Standard Error of Parameter Est. Constant 593.829 204.114 Children 90.629 3.305 Income –0.039 0.015 1. The value of the regression standard error is A) 0.015. B) 3.305. C) 204.14. D) 251.74. 2. Suppose we wish to test the hypotheses H 0 : 1 = 2 = 0, H a : at least one of the j is not 0 using the ANOVA F test. The P -value of the test is A) larger than 0.10. B) between 0.10 and 0.05. C) between 0.05 and 0.01 D) below 0.01. Page 1
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3. A 99% confidence interval for E 2 , the coefficient of the variable Income, is A) –0.039 ± 0.030. B) –0.039 ± 0.040. C) 0.015 ± 0.079. D) 0.015 ± 0.104. 4. The proportion of the variation in the variable Deaths that is explained by the explanatory variables Children and Income is A) 0.059. B) 0.159. C) 0.470. D) 0.941. 5. Based on the above analyses, we conclude A) the variable Income is statistically significant at level 0.05 as a predictor of the variable Deaths. B) the variable Income is statistically significant at level 0.05 as a predictor of the variable Deaths in a multiple regression model that includes the variable Children. C) the variable Income is not useful as a predictor of the variable Deaths and should be omitted from the analysis. D) the variable Children is not useful as a predictor of the variable Deaths, unless the variable Income is also present in the multiple regression model. 6. The statistical results in the above analyses are
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This note was uploaded on 09/25/2009 for the course IDS 371 taught by Professor Staff during the Spring '08 term at Ill. Chicago.

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PracticeExamNumber2 - A researcher was investigating...

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