8、The mean equity risk premium over a 40-year period is equal to 8.0 percent. The standard deviation of the sample is 12 percent. The standard error of the sample mean is closest to:
Decision rule: reject H0 if zcomputed > zcritical. Therefore, reject the null hypothesis because the computed test statistic of 2.60 (see the answer to Part 1) exceeds the critical z-value of 2.33.
The central limit theorem makes it appropriate to use the z-test with an unknown variance if the sample size is large enough (n ≥ 30), regardless of the distribution of the population. Since the t- and the z-distributions converge as sample size increases, either test is appropriate, although the t-test is a more conservative estimate.
6、A return series with 250 observations has a sample mean of 10 percent and a standard deviation of 15 percent. The standard error of the sample mean is closest to:
3、Margo Hinsdale is testing the null hypothesis that the population mean is less than or equal to 45. A random sample of 81 observations selected from this population produced a mean of 46.3. The population has a standard deviation of 4.5.
The value of the appropriate test statistic for the test of the population mean is:
发表于 2009-6-25 17:13
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