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  2. Homogeneity and heterogeneity (statistics) - Wikipedia

    en.wikipedia.org/wiki/Homogeneity_and...

    In statistics, a sequence of random variables is homoscedastic (/ ˌ h oʊ m oʊ s k ə ˈ d æ s t ɪ k /) if all its random variables have the same finite variance; this is also known as homogeneity of variance. The complementary notion is called heteroscedasticity, also known as heterogeneity of variance.

  3. Homoscedasticity and heteroscedasticity - Wikipedia

    en.wikipedia.org/wiki/Homoscedasticity_and...

    In statistics, a sequence of random variables is homoscedastic (/ ˌ h oʊ m oʊ s k ə ˈ d æ s t ɪ k /) if all its random variables have the same finite variance; this is also known as homogeneity of variance. The complementary notion is called heteroscedasticity, also known as heterogeneity of variance.

  4. Bartlett's test - Wikipedia

    en.wikipedia.org/wiki/Bartlett's_test

    The test procedure due to M.S.E (Mean Square Error/Estimator) Bartlett test is represented here. This test procedure is based on the statistic whose sampling distribution is approximately a Chi-Square distribution with ( k − 1) degrees of freedom, where k is the number of random samples, which may vary in size and are each drawn from ...

  5. Diversity index - Wikipedia

    en.wikipedia.org/wiki/Diversity_index

    This equation is also equal to the weighted arithmetic mean of the proportional abundances p i of the types of interest, with the proportional abundances themselves being used as the weights. [2] Proportional abundances are by definition constrained to values between zero and one, but it is a weighted arithmetic mean, hence λ ≥ 1/ R , which ...

  6. Heteroskedasticity-consistent standard errors - Wikipedia

    en.wikipedia.org/wiki/Heteroskedasticity...

    Generalized estimating equations; Weighted least squares, an alternative formulation; White test — a test for whether heteroskedasticity is present. Newey–West estimator; Quasi-maximum likelihood estimate

  7. Data transformation (statistics) - Wikipedia

    en.wikipedia.org/wiki/Data_transformation...

    Equation: = + Meaning: A unit increase in X is associated with an average of b units increase in Y. Equation: ⁡ = + (From exponentiating both sides of the equation: =) Meaning: A unit increase in X is associated with an average increase of b units in ⁡ (), or equivalently, Y increases on an average by a multiplicative factor of .

  8. Overdispersion - Wikipedia

    en.wikipedia.org/wiki/Overdispersion

    In statistics, overdispersion is the presence of greater variability (statistical dispersion) in a data set than would be expected based on a given statistical model. A common task in applied statistics is choosing a parametric model to fit a given set of empirical observations.

  9. Brown–Forsythe test - Wikipedia

    en.wikipedia.org/wiki/Brown–Forsythe_test

    Using the mean provided the best power for symmetric, moderate-tailed, distributions. O'Brien tested several ways of using the traditional analysis of variance to test heterogeneity of spread in factorial designs with equal or unequal sample sizes.