NO.PZ2023061301000027
问题如下：
Which of the following statements is correct regarding the chi-square test of
independence?
选项：
A.
The test has a one-sided rejection region.
B.
The null hypothesis is that the two groups are dependent.
C.
If there are two categories, each with three levels or groups, there are six
degrees of freedom.
解释：
A is correct. The test statistic includes squared differences between the observed
and expected values, so the test involves only one side, the right side. B is incorrect
because the null hypothesis is that the groups are independent, and C is
incorrect because with three levels of groups for the two categorical variables,
there are four degrees of freedom.
请问老师，b选项错在哪里呀？
