Author(s)

E. Artes, M. Rueda & A. Arcos

Abstract

The problem of estimation of a finite population mean for the current oc- casion based on the samples selected over two occasions has been consid- ered. For the case when the auxiliary variables are negatively correlated, a double-sampling product estimate from the matched portion of the sample is presented. Expressions for optimum estimator and its variance have been derived. The gain in efficiency of the combined estimate over the direct estimate using no information gathered on the first occasion is computed. 1 Introduction Study of marine ecology has been strongly motivated by the deve- lopment and conservation of fisheries and the longstanding value to society offish as food. The fish

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