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A Constrained Cook-Jacobson Model of Visibility Bias
Marc A. Evans and Douglas G. Bonett
Vol. 49, No. 3 (Sep., 1993), pp. 853-859
Published by: International Biometric Society
Stable URL: http://www.jstor.org/stable/2532204
Page Count: 7
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A generalization of the Cook-Jacobson model for assessing closed population size from aerial survey data is presented. Estimators for the number of animal groups of a specific size and group sighting probabilities are developed, along with the corresponding variance estimators. Estimation is based on a log-linear model subject to linear and nonlinear constraints. Of particular interest are constraints that relate group size to the group sighting probabilities. A Wald test is presented for assessing the appropriateness of the proposed constraints. Substantial reductions in variance estimates can be obtained for the constrained model when compared with variance estimates from the saturated or unconstrained Cook-Jacobson model.
Biometrics © 1993 International Biometric Society