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Hellin's Law
Hellin's law, also called Hellin-Zeleny's law, is an empirical observation in demography that the approximate rate of multiple birth A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such bir ...s is one n-tuple birth per 89n-1 singleton births: twin births occur about once per 89 singleton births, triplets about once per 892, quadruplets about once per 893, and so on. Origin Throughout the 1800s demographics registers were becoming more common in Europe, which generated data sets in different administrative regions. There was interest in twin research, and many demographers began studying patterns in birth rates. Analysis by Veit in 1855 of a Prussian data set covering 1826 to 1849 showed the numbers of twin, triplet, and quadruplet maternities were respectively one for every 89, 7910, and 37 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demography
Demography () is the statistics, statistical study of populations, especially human beings. Demographic analysis examines and measures the dimensions and Population dynamics, dynamics of populations; it can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity. Educational institutions usually treat demography as a field of sociology, though there are a number of independent demography departments. These methods have primarily been developed to study human populations, but are extended to a variety of areas where researchers want to know how populations of Social actions, social actors can change across time through processes of birth, death, and Human migration, migration. In the context of human biological populations, demographic analysis uses Public records, administrative records to develop an independent Approximation, estimate of the population. Demographic analysis estimates are often considered a reliable stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Birth
A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such births are often named according to the number of offspring, as in ''twins'' and ''triplets''. In non-humans, the whole group may also be referred to as a ''litter'', and multiple births may be more common than single births. Multiple births in humans are the exception and can be exceptionally rare in the largest mammals. A multiple pregnancy may be the result of the fertilization of a single egg that then splits to create identical fetuses, or it may be the result of the fertilization of multiple eggs that create fraternal ("non-identical") fetuses, or it may be a combination of these factors. A multiple pregnancy from a single zygote is called ''monozygotic'', from two zygotes is called ''dizygotic'', or from three or more zygotes is calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civil Registration
Civil registration is the system by which a government records the vital events (births, marriages, and deaths) of its citizens and residents. The resulting repository or database has different names in different countries and even in different US states. It can be called a civil registry, civil register (but this is also an official term for an individual file of a vital event), vital records, and other terms, and the office responsible for receiving the registrations can be called a bureau of vital statistics, registry of vital records and statistics, registrar, registry, register, registry office (officially register office), or population registry. The primary purpose of civil registration is to create a legal document (usually called a ''certificate'') that can be used to establish and protect the rights of individuals. A secondary purpose is to create a data source for the compilation of vital statistics. The United Nations General Assembly in 1979 adopted the Convent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Independence (probability Theory)
Independence is a fundamental notion in probability theory, as in statistics and the theory of stochastic processes. Two events are independent, statistically independent, or stochastically independent if, informally speaking, the occurrence of one does not affect the probability of occurrence of the other or, equivalently, does not affect the odds. Similarly, two random variables are independent if the realization of one does not affect the probability distribution of the other. When dealing with collections of more than two events, two notions of independence need to be distinguished. The events are called pairwise independent if any two events in the collection are independent of each other, while mutual independence (or collective independence) of events means, informally speaking, that each event is independent of any combination of other events in the collection. A similar notion exists for collections of random variables. Mutual independence implies pairwise independence ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australia
Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, smaller islands. With an area of , Australia is the largest country by area in Oceania and the world's List of countries and dependencies by area, sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a Megadiverse countries, megadiverse country, and its size gives it a wide variety of landscapes and climates, with Deserts of Australia, deserts in the centre, tropical Forests of Australia, rainforests in the north-east, and List of mountains in Australia, mountain ranges in the south-east. The ancestors of Aboriginal Australians began arriving from south east Asia approximately Early human migrations#Nearby Oceania, 65,000 years ago, during the Last Glacial Period, last i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Demography
Demography () is the statistics, statistical study of populations, especially human beings. Demographic analysis examines and measures the dimensions and Population dynamics, dynamics of populations; it can cover whole societies or groups defined by criteria such as education, nationality, religion, and ethnicity. Educational institutions usually treat demography as a field of sociology, though there are a number of independent demography departments. These methods have primarily been developed to study human populations, but are extended to a variety of areas where researchers want to know how populations of Social actions, social actors can change across time through processes of birth, death, and Human migration, migration. In the context of human biological populations, demographic analysis uses Public records, administrative records to develop an independent Approximation, estimate of the population. Demographic analysis estimates are often considered a reliable stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Births
A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such births are often named according to the number of offspring, as in ''twins'' and ''triplets''. In non-humans, the whole group may also be referred to as a ''litter'', and multiple births may be more common than single births. Multiple births in humans are the exception and can be exceptionally rare in the largest mammals. A multiple pregnancy may be the result of the fertilization of a single egg that then splits to create identical fetuses, or it may be the result of the fertilization of multiple eggs that create fraternal ("non-identical") fetuses, or it may be a combination of these factors. A multiple pregnancy from a single zygote is called ''monozygotic'', from two zygotes is called ''dizygotic'', or from three or more zygotes is calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
