The influence of outliers on a model for the estimation of crossbreeding parameters for weaning weight in a beef cattle herd
Data on 17348 weaning weight records from a beef cattle crossbreeding operation were used to determine the effect of outliers on regression coefficients. Different criteria were used for detecting potential influential points. Eliminating a small number (932 or 5.4%) influential points resulted in the improvement of the model fitted. The R2 values increased from 41% to 49% while the mean square error was reduced from 672.9 to 500.4. The use of diagnostic statistics for detecting influential observations is recommended before any analysis is performed. © South African Society for Animal Science.