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  2. Grouped data - Wikipedia

    en.wikipedia.org/wiki/Grouped_data

    In this formula, x refers to the midpoint of the class intervals, and f is the class frequency. Note that the result of this will be different from the sample mean of the ungrouped data. The mean for the grouped data in the above example, can be calculated as follows:

  3. Error function - Wikipedia

    en.wikipedia.org/wiki/Error_function

    Given a random variable X ~ Norm[μ,σ] (a normal distribution with mean μ and standard deviation σ) and a constant L > μ, it can be shown via integration by substitution: [] = + ⁡ ⁡ (()) where A and B are certain numeric constants.

  4. Sheppard's correction - Wikipedia

    en.wikipedia.org/wiki/Sheppard's_correction

    Sheppard, W.F. (1897). "On the Calculation of the most Probable Values of Frequency-Constants, for Data arranged according to Equidistant Division of a Scale".

  5. Fixed effects model - Wikipedia

    en.wikipedia.org/wiki/Fixed_effects_model

    The group means could be modeled as fixed or random effects for each grouping. In a fixed effects model each group mean is a group-specific fixed quantity. In panel data where longitudinal observations exist for the same subject, fixed effects represent the subject-specific means.

  6. 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 ...

  7. Proportionate reduction of error - Wikipedia

    en.wikipedia.org/wiki/Proportionate_reduction_of...

    The summary statistics is particularly useful and popular when used to evaluate models where the dependent variable is binary, taking on values {0,1}. Example [ edit ]

  8. Errors-in-variables model - Wikipedia

    en.wikipedia.org/wiki/Errors-in-variables_model

    Linear errors-in-variables models were studied first, probably because linear models were so widely used and they are easier than non-linear ones. Unlike standard least squares regression (OLS), extending errors in variables regression (EiV) from the simple to the multivariable case is not straightforward, unless one treats all variables in the same way i.e. assume equal reliability.

  9. Template:Google Wikipedia/doc - Wikipedia

    en.wikipedia.org/wiki/Template:Google_Wikipedia/doc

    This template is a cut-down instance of the more general {{Google custom}} template. You may wish to make similar templates if you need to create repetitive links to other portions of Wikipedia that {{Google custom}} can search. This saves much typing compared to using {{Google custom}} for each link.