英语翻译

题目

英语翻译
一个随机过程,如果它的数学期望、方差不随时间变化,且自相关函数仅是它们时间间隔的函数而与绝对时间无关,则称之为平稳随机过程,相应的时间序列称为平稳时间序列,否则为非平稳时间序列.

答案

A stochastic process,if its mathematic expectation,the variance along with the time variation,the correlation function are only not their time-gap functions for the time being,but has nothing to do with the absolute time,then called that it the stationary random process,the corresponding time series is called the steady time series,otherwise for non-steady time series