方差是在概率论和统计方差衡量随机变量或一组数据时离散程度的度量。概率论中方差用来度量随机变量和其数学期望(即均值)之间的偏离程度。统计中的方差(样本方差)是每个样本值与全体样本值的平均数之差的平方值的平均数。在许多实际问题中,研究方差即偏离程度有着重要意义。 方差是衡量源数据和期望值相差的度量值。
...n平均差使用绝对值没有正负所以不便于在统计中运用。第二节方差和标准差第二节方差和标准差一、方差和标准差、方差方差(variance,,S):各数据与平均数差数的平方和的平均值称为方差也称为变异数。
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... probability几率,机率 square deviation方差 variation coefficient异常变化系数 ...
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... mean squared departure 均方偏差 mean square deviation 均方偏差;方差;均方差 mean square error 均方误差 ...
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协方差 [数] covariance ; cov ; Kovarianz ; product moment
均方差 mean squared error ; RMSE ; MSE
协方差矩阵 [数] covariance matrix ; cov ; VARIANCE-COVARIANCE MATRIX
方差分析 ANOVA ; [数] Analysis of Variance ; one-way anova ; way ANOVA
单因素方差分析 One-Way ANOVA ; ANOVA ; one-factor ANOVA ; single factor analysis of variance
方差齐性 [数] Homogeneity of variance ; Homoscedascity ; equality of variance ; homogeneity variance
合并方差 Polled variance ; combined variance
方差互换 variance swap
方差比 f ratio ; ratio of variance ; variance e ratio
Most theoretical models in financial economics measure risk as variance.
金融经济学中,大部分的理论模型用方差来度量风险。
参考来源 - 风险度量与组合投资新方法——双侧部分矩模型Variance analysis and contrast method are applied to select color space.
首先采用方差分析方法和对比度方法进行彩色空间的选择。
参考来源 - 模糊C·2,447,543篇论文数据,部分数据来源于NoteExpress
比赛结果的胜负双方差距极小。
这方面尤其如此,因为贵国那个地区的不同地方差别很大。
This is especially so, since there are such vast differences between the various places in that part of your country.
协变和逆变的区别对于张量的计算尤为重要,这往往会出现混合方差。
The distinction between covariance and contravariance is important for computations with tensors, which often have mixed variance.
There's no correlation between them ... and that means that the variance-- and I want to talk about equally-weighted portfolio.
它们之间没有相关性,也就是说。。。方差-,我想讲一下,权重相等的投资组合。
One more thing, I said they're not independent, so we have to talk about the covariance between the returns.
还有,我说过它们不是相互独立的,因此我们还需要讨论两个收益率的协方差。
If you're comparing two portfolios with the same expected return, then you want the one with the lower variance.
比较两个有相同预期收益率的投资组合时,你会选择方差小的那一个。
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