Order statistics and related general models of ordered random variables are important in statistical theory and its applications. The independent and identically distributed random variables, that can be interpreted as results of an experiment measuring values of a certain random variable arranged in order of magnitude, are called order statistics. In statistical model of many experiments, for instance in reliability analysis, life time studies, in testing of strength of materials, etc., the realizations arise in nondecreasing order, therefore the use of order statistics is necessary. Furthermore, order statistics are extensively used in statistical inferences; in the estimation theory and hypothesis testing. Together with rank statistics, order statistics are among the most fundamental tools in non-parametric statistics.
