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  2. Propagation of uncertainty - Wikipedia

    en.wikipedia.org/wiki/Propagation_of_uncertainty

    Any non-linear differentiable function, (,), of two variables, and , can be expanded as + +. If we take the variance on both sides and use the formula [11] for the variance of a linear combination of variables ⁡ (+) = ⁡ + ⁡ + ⁡ (,), then we obtain | | + | | +, where is the standard deviation of the function , is the standard deviation of , is the standard deviation of and = is the ...

  3. Algorithms for calculating variance - Wikipedia

    en.wikipedia.org/wiki/Algorithms_for_calculating...

    Algorithms for calculating variance play a major role in computational statistics.A key difficulty 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 when dealing with large values.

  4. Price variance - Wikipedia

    en.wikipedia.org/wiki/Price_Variance

    Price variance (Vmp) is a term used in cost accounting which denotes the difference between the expected cost of an item (standard cost) and the actual cost at the time of purchase. [1] The price of an item is often affected by the quantity of items ordered, and this is taken into consideration.

  5. Direct material total variance - Wikipedia

    en.wikipedia.org/wiki/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 components: the direct material price variance, the direct material usage variance.

  6. Direct material usage variance - Wikipedia

    en.wikipedia.org/wiki/Direct_material_usage_variance

    In variance analysis, 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 materials used, valued at the standard cost per unit of material.

  7. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    using a target variance for an estimate to be derived from the sample eventually obtained, i.e., if a high precision is required (narrow confidence interval) this translates to a low target variance of the estimator. the use of a power target, i.e. the power of statistical test to be applied once the sample is collected.

  8. Variance - Wikipedia

    en.wikipedia.org/wiki/Variance

    There are two distinct concepts that are both called "variance". One, as discussed above, is part of a theoretical probability distribution and is defined by an equation. The other variance is a characteristic of a set of observations. When variance is calculated from observations, those observations are typically measured from a real-world system.

  9. Sensitivity analysis - Wikipedia

    en.wikipedia.org/wiki/Sensitivity_analysis

    Variance-based methods [27] are a class of probabilistic approaches which quantify the input and output uncertainties as random variables, represented via their probability distributions, and decompose the output variance into parts attributable to input variables and combinations of variables. The sensitivity of the output to an input variable ...