# variance

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**Algorithms for calculating variance**— play a major role in statistical computing. A key problem in the design of good algorithms for this problem is that formulas for the variance may involve sums of squares, which can lead to numerical instability as well as to arithmetic overflow… …102

**Allan variance**— The Allan variance, named after David W. Allan, is a measurement of stability in clocks and oscillators. It is also known as the two sample variance.It is defined as one half of the time average of the squares of the differences between… …103

**Direct material total variance**— In variance analysis (accounting) direct material total variance is the difference between the actual cost of actual number of units produced and its budgeted cost in terms of material. Direct material total variance can be divided into two… …104

**Hadamard variance**— The Hadamard variance (HVAR) is a measure of stability of clocks and oscillators. It uses 3 sample variance, not unlike the Allan variance, which uses 2 sample variance. But unlike the Allan variance, the Hadamard variance is able to converge a… …105

**Direct material usage variance**— In variance analysis (accounting) direct material usage (efficiency, quantity) variance is the difference between the standard quantity of materials that should have been used for the number of units actually produced, and the actual quantity of… …106

**Sales variance**— is the difference between actual sales and budget sales. It is used to measure the performance of a sales function, and/or analyze business results to better understand market conditions.There are two reasons actual sales can vary from planned… …107

**Direct material price variance**— In variance analysis (accounting) direct material price variance is the difference between the standard cost and the actual cost for the actual quantity of material used or purchased. It is one of the two components (the other is direct material… …108

**Conditional variance**— In probability theory and statistics, a conditional variance is the variance of a conditional probability distribution. Particularly in econometrics, the conditional variance is also known as the scedastic function or skedastic function.… …109

**Matrice De Variance-Covariance**— Une matrice de variance covariance est une matrice carrée caractérisant les interactions (linéaires) entre p variables aléatoires . Sommaire 1 Définition 2 Propriétés …110

**Law of total variance**— In probability theory, the law of total variance or variance decomposition formula states that if X and Y are random variables on the same probability space, and the variance of X is finite, then:operatorname{var}(X)=operatorname{E}(operatorname{v… …