NO.PZ2020010302000007
问题如下：
What are the median and interquartile range? When is the median equal to the mean?
解释：
The median is the point where 50% of the probability is located on either side. It may not be unique in discrete distributions, although it is common to choose the smallest value where this condition is satisfied.
The IQR is the difference between the 25% and 75% quantiles. These are the points where 25% and 75% of the probability of the random variable lies to the left. This difference is a measure of spread that is like the standard deviation.
The median is equal to the mean in any symmetric distribution if the first moment exists (is finite).
老师好，
1、能否举一个“线性插值之类的方法找中位数”的例子呢？
2、为什么一阶导存在可以理解为有均值呢？只要有数就有均值，和一阶导有什么关系呢？
3、“对于对称的分布，均值等于中位数”这里仅指连续分布？
