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  2. Homogeneity and heterogeneity (statistics) - Wikipedia

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

    They relate to the validity of the often convenient assumption that the statistical properties of any one part of an overall dataset are the same as any other part. In meta-analysis, which combines the data from several studies, homogeneity measures the differences or similarities between the several studies (see also Study heterogeneity).

  3. External validity - Wikipedia

    en.wikipedia.org/wiki/External_validity

    External validity is the validity of applying the conclusions of a scientific study outside the context of that study. [1] In other words, it is the extent to which the results of a study can generalize or transport to other situations, people, stimuli, and times.

  4. Homoscedasticity and heteroscedasticity - Wikipedia

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

    Thus, regression analysis using heteroscedastic data will still provide an unbiased estimate for the relationship between the predictor variable and the outcome, but standard errors and therefore inferences obtained from data analysis are suspect. Biased standard errors lead to biased inference, so results of hypothesis tests are possibly wrong.

  5. Study heterogeneity - Wikipedia

    en.wikipedia.org/wiki/Study_heterogeneity

    Statistical testing for a non-zero heterogeneity variance is often done based on Cochran's Q [13] or related test procedures. This common procedure however is questionable for several reasons, namely, the low power of such tests [14] especially in the very common case of only few estimates being combined in the analysis, [15] [7] as well as the specification of homogeneity as the null ...

  6. Multitrait-multimethod matrix - Wikipedia

    en.wikipedia.org/wiki/Multitrait-multimethod_matrix

    The multitrait-multimethod (MTMM) matrix is an approach to examining construct validity developed by Campbell and Fiske (1959). [1] It organizes convergent and discriminant validity evidence for comparison of how a measure relates to other measures.

  7. Homogeneity and heterogeneity - Wikipedia

    en.wikipedia.org/wiki/Homogeneity_and_heterogeneity

    Homogeneity and heterogeneity; only ' b ' is homogeneous Homogeneity and heterogeneity are concepts relating to the uniformity of a substance, process or image.A homogeneous feature is uniform in composition or character (i.e., color, shape, size, weight, height, distribution, texture, language, income, disease, temperature, radioactivity, architectural design, etc.); one that is heterogeneous ...

  8. Endogeneity (econometrics) - Wikipedia

    en.wikipedia.org/wiki/Endogeneity_(econometrics)

    The endogeneity problem is particularly relevant in the context of time series analysis of causal processes. It is common for some factors within a causal system to be dependent for their value in period t on the values of other factors in the causal system in period t − 1. Suppose that the level of pest infestation is independent of all ...

  9. Diachrony and synchrony - Wikipedia

    en.wikipedia.org/wiki/Diachrony_and_synchrony

    This latter approach is what surface analysis often relies on, as a given composition may not have appeared synchronously in history. The terms synchrony and diachrony are often associated with historical linguist Ferdinand de Saussure , who considered the synchronic perspective as systematic but argued that language change is too unpredictable ...