Abstract
Several methods for analyzing proportions from split-plot and repeated measures experiments are illustrated and compared. One approach simply uses analysis of variance for the usual linear mixed model fit to split-plot and repeated measures experiments. Alternatively, logistic regression analysis is considered and a so-called robust estimate of the covariance matrix is used to adjust for possible correlations among responses. Finally, a quasi-likelihood approach to logistic regression analysis that requires more explicit specification of the covariance structure for the observed proportions is considered. These methods are illustrated with the analyses of data from a repeated measures study of acorn consumption by blue jays and a study of the effects of several environmental factors on nest predation for ground nesting birds.
Keywords
Logistic regression, robust covariance estimation, quasi-likelihood
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Recommended Citation
Koehler, Kenneth J.
(1996).
"ANALYSIS OF PROPORTIONS FROM SPLIT-PLOT AND REPEATED MEASURES EXPERIMENTS,"
Conference on Applied Statistics in Agriculture.
https://doi.org/10.4148/2475-7772.1317
ANALYSIS OF PROPORTIONS FROM SPLIT-PLOT AND REPEATED MEASURES EXPERIMENTS
Several methods for analyzing proportions from split-plot and repeated measures experiments are illustrated and compared. One approach simply uses analysis of variance for the usual linear mixed model fit to split-plot and repeated measures experiments. Alternatively, logistic regression analysis is considered and a so-called robust estimate of the covariance matrix is used to adjust for possible correlations among responses. Finally, a quasi-likelihood approach to logistic regression analysis that requires more explicit specification of the covariance structure for the observed proportions is considered. These methods are illustrated with the analyses of data from a repeated measures study of acorn consumption by blue jays and a study of the effects of several environmental factors on nest predation for ground nesting birds.
