问题如下：
Which of the following sequences best represents the relative sizes of the mean, median, and mode for a positively skewed unimodal distribution?
选项：
A.mode ≤ median ≤ mean
mode < median < mean
mean < median < mode
解释：
B is correct. For the positively skewed unimodal distribution, the mode is less than the median, which is less than the mean.
A is incorrect because, for the positively skewed unimodal distribution, the mode is less than the median (not less than or equal to), which is less than (not less than or equal to) the mean.
C is incorrect because, for the negatively (not positively) skewed unimodal distribution, the mean is less than the median, which is less than the mode.
老师，比如下面这个总体，是不是应该是右偏的，那mode=1，median=1,等号不是成立吗？
{0，0，1，1，1，1，1，1，1，1，2，2，3}
