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A Proposed Test of the Difference Between the Means of Monozygotic And Dizygotic Twins

Published online by Cambridge University Press:  01 August 2014

J.C. Christian  and
J.A. Norton Jr.
J.C. Christian*
Affiliation:
Departments of Medical Genetics and Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
J.A. Norton Jr.
Affiliation:
Departments of Medical Genetics and Psychiatry, Indiana University School of Medicine, Indianapolis, Indiana, USA
*
Department of Medical Genetics, Indiana University School of Medicine, 1100 West Michigan Street, Indianapolis, Indiana 46202, USA

Abstract

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The rationale for using an approximate t′ test of the difference between the means of MZ and DZ twins is presented. This test avoids pooling the among-MZ and among-DZ twin-pair mean squares and has approximate degrees of freedom based upon the relative number of MZ and DZ twin pairs as well as the relative sizes of the among-MZ and among-DZ twin-pair mean squares. Sampling experiments simulating twin studies were used to show that the rate of Type I error for this t′ test was appropriate while other tests could give either too many or too few Type I errors depending upon the relative sizes of the mean squares and the relative numbers of MZ and DZ twin pairs.

Type
Research Article
Information
Acta geneticae medicae et gemellologiae: twin research , Volume 26 , Issue 1 , January 1977 , pp. 49 - 53
Copyright
Copyright © The International Society for Twin Studies 1977

References

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