问题如下：
Which of the following statements about one-side hypothesis test is most correct ?
选项：
A. We reject the null only if the evidence indicates that the population parameter is smaller or larger than the critical value.
B. Do not have Type I error.
C. We reject the null only if the evidence indicates that the test statistic is greater than or less than the critical value.
解释：
C is correct. By definition, one-side hypothesis test also called one-tailed hypothesis test, which reject rule is reject the null only if the evidence indicates that the test statistic is greater than or less than the critical value.
请问这道题为什么选c，不选a？ 课件上关于one-tailed的那一页，注意里讲的是“ for population parameter not sample statistic ” ； 教材里关于one-tailed hypotheses test 的原文叙述是“In contrast, Formulations 2 and 3 are each a one-sided hypothesis test (or one-tailed hypothesis test). For Formulations 2 and 3, we reject the null only if the evidence indicates that the population parameter is respectively greater than or less than θ0.”
