Statistical modelling of birth weight variability within litter in pigs Likelihood Quotienten Test Innerwurfvarianz (verallgemeinertes) lineares gemischtes Modell Gammaverteilung Test von zufälligen Effekten parametrisches Bootstrap within litter variation (generalized) linear mixed model gamma distribution test of random effects parametric bootstrap The study of sow reproduction traits is important in livestock science and production to increase animal survival and economic efficiency. This work deals with the detection of different effects on within litter variance of birth weight by applying different statistical models with different distributional assumptions. The piglets within one litter were separated by sex. The trait of sow was formed from the sample variances of birth weights within litter separated by sex to consider the sex effect on mean birth weight ...