NO.PZ2017092702000122
问题如下：
An analyst is examining a large sample with an unknown population variance. To test the hypothesis that the historical average return on an index is less than or equal to 6%, which of the following is the most appropriate test?
选项：
A.One-tailed z-test
B.Two-tailed z-test
C.One-tailed F-test
解释：
A is correct.
If the population sampled has unknown variance and the sample is large, a z-test may be used. Hypotheses involving "greater than" or "less than" postulations are one-sided (one-tailed). In this situation, the null and alternative hypotheses are stated as H0: μ ≤ 6% and Ha: μ > 6%, respectively. A one-tailed t-test is also acceptable in this case.
大样本下，如果方差未知，检验均值既可以用T检验，也可以用Z检验。 请问课件哪里哪页
