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Nonparametric evaluation of heritability by intra‐twin differences of mono‐ and dicygotic twins
Author(s) -
Von Eye A.,
Lienert G. A.
Publication year - 1980
Publication title -
biometrical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.108
H-Index - 63
eISSN - 1521-4036
pISSN - 0323-3847
DOI - 10.1002/bimj.4710220606
Subject(s) - heritability , nonparametric statistics , heredity , statistics , dizygotic twins , trait , twin study , mathematics , test (biology) , covariate , econometrics , psychology , biology , medicine , genetics , computer science , paleontology , obstetrics , programming language
Starting from intratwin differences x – x of two cotwins X and X in a specified trait (e.g. IQ) the following prediction was made from heredity assumption: intratwin differences will be larger in dizygotic than in monozygotic twins and will, from theoretical reasons, not be distributed normally. Therefore nonparametric testing is suggested either by U ‐test or by median‐test depending on whether the differences differ in dispersion. Additionally descriptive measures of heritability were derived from the respective test statistics in such a way as to correspond to parametric heritability coefficients.