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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.
Genetic heterogeneity occurs through the production of single or similar phenotypes through different genetic mechanisms. There are two types of genetic heterogeneity: allelic heterogeneity, which occurs when a similar phenotype is produced by different alleles within the same gene; and locus heterogeneity, which occurs when a similar phenotype is produced by mutations at different loci.
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 ...
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 ...
The spatial local heterogeneity categorises the geographic phenomena whose its attributes' values are significantly similar within a directly local neighbourhood, but which significantly differ in the nearby surrounding-areas beyond this directly local neighbourhood (e.g. hot spots, cold spots).
A heterogeneous taxon, a taxon that contains a great variety of individuals or sub-taxa; usually this implies that the taxon is an artificial grouping; Genetic heterogeneity, multiple origins causing the same disorder in different individuals. Allelic heterogeneity, different mutations at the same locus causing the same disorder.
Tissue heterogeneity affects commonly used, reference gene expression datasets such as the Genotype-Tissue Expression Project (GTEx). [2] Cancer samples often display varying degree of heterogeneity, because they consist of tumor cells of multiple subclones, immune cells, and other cell types.
Phenotypic heterogeneity describes different mutations in the same gene that can sometimes give rise to strikingly different phenotypes.. E.g., certain loss-of-function mutations in the RET gene, which encodes a receptor tyrosine kinase, can cause dominantly inherited failure of development of colonic ganglia, leading to defective colonic motility and severe chronic constipation (Hirschsprung ...