Order statistic
（重定向自Order statistics）
![Probability density functions of the order statistics for a sample of size n = 5 from an exponential distribution with unit scale parameter.](/Images/godic/202501/31/Order_Statistics_Exponential_PDF.svg5544.png")
In statistics, the kth order statistic of a statistical sample is equal to its kth-smallest value. Together with rank statistics, order statistics are among the most fundamental tools in non-parametric statistics and inference.
Important special cases of the order statistics are the minimum and maximum value of a sample, and (with some qualifications discussed below) the sample median and other sample quantiles.