“variance”的概念、定义、习题解题方法及翻译-数学辞典

单词

variance

释义

variance

A measure of the dispersion of a random variable or of a sample. For a random variable X, the population variance is the second moment about the population mean μ and is equal to E((X − μ)2) (see expected value). It is usually denoted by σ2 or Var(X). For a sample, the sample variance, denoted by s2, is the second moment of the data about the sample mean $inline$ , but the denominator is usually taken as n − 1 rather than n in order to make it an unbiased estimator of the population variance. So

For computational purposes, notice that $inline$ .

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数学辞典收录了4151条数学词条，基本涵盖了常用数学知识及数学英语单词词组的翻译及用法，是数学学习的有利工具。