Q1. Ryan McKeeler and Howard Hu, two junior statisticians, were discussing the relation between confidence intervals and hypothesis tests. During their discussion each of them made the following statement: McKeeler: A confidence interval for a two-tailed hypothesis test is calculated as adding and subtracting the product of the standard error and the critical value from the sample statistic. For example, for a level of confidence of 68%, there is a 32% probability that the true population parameter is contained in the interval. Hu: A 99% confidence interval uses a critical value associated with a given distribution at the 1% level of significance. A hypothesis test would compare a calculated test statistic to that critical value. As such, the confidence interval is the range for the test statistic within which a researcher would not reject the null hypothesis for a two-tailed hypothesis test about the value of the population mean of the random variable. With respect to the statements made by McKeeler and Hu: A) both are correct. B) only one is correct. C) both are incorrect.
Q2. Given a mean of 10% and a standard deviation of 14%, what is a 95% confidence interval for the return next year? A) -17.44% to 37.44%. B) -4.00% to 24.00%. C) -17.00% to 38.00%.
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发表于 2009-1-13 16:03
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