问题如下：
Which of the following descriptions on a two-tailed hypothesis test is least correct?
选项：
A.A two-tailed test is less directive than a one-tailed test.
B.The alternative hypotheses of one-tailed tests has less impacts on the researcher's beliefs than the alternative hypotheses of two-tailed tests.
C.Under the same significance level, the absolute value of two-tailed test's rejection points is larger than the one of one-tailed test.
解释：
B is correct. A two-tailed test is a “not equal to” alternative hypothesis, while a one-tailed test is a “greater than” or “less than” alternative hypothesis. “greater than” or “less than” alternative hypotheses reflect the beliefs of the researcher more strongly than a "not equal to" alternative hypothesis.
“A可以理解为双尾检验说的是例如均值“不等于”一个确定的数，不等于就包括两种情况，大于和小于。而单尾检验明确的指出了均值就是大于或者就是小于某一个数，所以单尾检验的指向性或者说反应研究人员的信心程度更强一些。
B选项说的其实是双尾检验比单尾检验更能反映研究者的信念，这个描述其实是错误的。因为单尾检验的备择假设有大于和小于两种情况，而双尾检验的备择假设只是不等于，可能是大于，也可能是小于，没有单尾检验这么明确。所以结论应该是：单尾检验比双尾检验更能反映研究者的信念，也就是说研究的方向会更加明确。”
对于AB选项，我看到了以上解释。还不是很清楚AB之间的区别，到底是单侧检验更明确还是双侧检验？
