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| Registros recuperados: 24 | |
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| Cox, Nicholas J.. |
| Counting panels, and more generally groups, is sometimes possible in Stata through a reduction command (e.g., collapse, contract, statsby) that produces a smaller dataset or through a tabulation command. Yet there are also many problems, especially with irregular sets of observations for varying times, that do not yield easily to this approach. This column focuses on techniques for answering such questions while maintaining the same data structure. Especially useful are the Stata commands by: and egen and indicator variables constructed for the purpose. With by: we often exploit the fact that subscripts are defined within group, not within dataset. egen functions are often used to produce group-level statistics. Tagging each group just once ensures that... |
| Tipo: Article |
Palavras-chave: Data management; Panels; Research Methods/ Statistical Methods. |
| Ano: 2007 |
URL: http://purl.umn.edu/119295 |
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| Klein,Daniela Regina; Vale,Marcos Martinez do; Silva,Mariana Fernandes Ribas da; Kuhn,Micheli Faccin; Branco,Tatiane; Santos,Mauricio Portella dos. |
| ABSTRACT The hatchery is one of the most important segments of the poultry chain, and generates an abundance of data, which, when analyzed, allow for identifying critical points of the process . The aim of this study was to evaluate the applicability of the data mining technique to databases of egg incubation of broiler breeders and laying hen breeders. The study uses a database recording egg incubation from broiler breeders housed in pens with shavings used for litters in natural mating, as well as laying hen breeders housed in cages using an artificial insemination mating system. The data mining technique (DM) was applied to analyses in a classification task, using the type of breeder and house system for delineating classes. The database was analyzed in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Attribute selection; Classification tree; Data management; Data mining and information technology. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162020000400501 |
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| Registros recuperados: 24 | |
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