title: Analysis of the human sex ratio by using overdispersion models.
abstract: Data from nineteenth-century Germany are reanalyzed to determine how the probability for having a child of each sex changes with family size. The data, collected by A. Geissler, concern some 1 million birth registrations and 3.7 million births occurring in Saxony between 1876 and 1885. Three models are fitted to the data. "The multiplicative and beta-binomial models provide similar fits, substantially better than that of the double-binomial model. All models show that both the probability that the child is a boy and the dispersion are greater in larger families. There is also some indication that a point probability mass is needed for families containing children uniquely of one sex."
authors.forename: J K
authors.initials: JK
authors.lastname: Lindsey
authors.forename: P M
authors.initials: PM
authors.lastname: Altham
mesh_terms: D003710:Demography; D019049:Developed Countries; D005060:Europe; D005191:Family Characteristics; D005858:Germany; D008962:Models, Theoretical; D011153:Population; D011154:Population Characteristics; D012106:Research; D017678:Sex Distribution; D012737:Sex Factors; D012744:Sex Ratio
keywords: Demographic Factors; Developed Countries; Europe; Family And Household; Family Characteristics; Family Size; Germany; Historical Survey; Models, Theoretical; Population; Population Characteristics; Research Methodology; Sex Distribution; Sex Factors; Sex Ratio; Western Europe