Data/hora: 01/06/2024 07:26:59

Provedor de dados: 	5	
País: 	France	
Título: 	Estimateurs d'indices d'abondance dans le cas d'échantillonnages stratifiés	
Autores: 	Bertrand, Jacques; Chevalier, Robert.	
Data: 	1988	
Ano: 	1988	
Resumo: 	One of the primary uses of trawl survey data is the estimation of abundance of the species involved. But these direct estimates give results with generally a high variability. Reducing this latter is one of the main problems for the scientists involved in such a research. Methods to achieve a better efficiency have been implemented. Nevertheless estimations remain highly variable, so the information on the changes in population, enclosed in the observed series of survey indices is mixed with a noise component result of both the survey sampling variability and effect of uncontrolled factors. PENNING'roN ( 1985) proposed time series models to filter measurement error from the signal. However the length of the series does not always allow using time series methodology. So for a shortest series we have tried smoothing the observed indices using the variance analysis model to calculate parametric estimators. It is assumed that the data are measured with multiplicative random errors. The values so estimated are more efficient than the classical estimates. The indices so obtained for age group 3 (recrui tement) are more closely related to the VPA estimates than the current ones.	
Tipo: 	Text	
Idioma: 	Francês	
Identificador: 	http://archimer.ifremer.fr/doc/00388/49925/50499.pdf

http://archimer.ifremer.fr/doc/00388/49925/	
Formato: 	application/pdf	
Fonte: 	1988 Conseil International pour l' Exploration de la Mer

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