30)Mary used a sample of 68 large U.S. cities to estimate the relationship between Crime(annual property crimes per 100,000 persons) and Income(median annual income per capita, in dollars). Her estimated regression equation was Crime= 428 + 0.050 Income.If Incomedecreases by 1000, we would expect that Crimewill: A. increase by 428. B. decrease by 50. C. increase by 500. D. remain unchanged.31)Simple regression analysis means that: 32)Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the time to perform an appendectomy. A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes with a variance of 16 minutes. For a right-tailed test of means (assume equal variances), the test statistic is:

833)Guidelines for the Jolly Blue Giant Health Insurance Company say that the average hospitalization for a triple hernia operation should not exceed 30 hours. A diligent auditor studied records of 16 randomly chosen triple hernia operations at Hackmore Hospital and found a mean hospital stay of 40 hours with a standard deviation of 20 hours. "Aha!" she cried, "the average stay exceeds the guideline." At α= .025, the critical value for a right-tailed test of her hypothesis is: 34)Guidelines for the Jolly Blue Giant Health Insurance Company say that the average hospitalization for a triple hernia operation should not exceed 30 hours. A diligent auditor studied records of 16 randomly chosen triple hernia operations at Hackmore Hospital and found a mean hospital stay of 40 hours with a standard deviation of 20 hours. "Aha!" she cried, "the average stay exceeds the guideline." The value of the test statisticfor her hypothesis is: A. 2.080 B. 0.481 C. 1.866 D. 2.000

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- Fall '07
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- Business, Statistics, Normal Distribution, Standard Deviation, Null hypothesis, Statistical hypothesis testing