ML estimation and an efficiency study for mean estimators in spatially correlated repeated arrays

For spatially correlated repeated arrays, a simple method is proposed for maximum likelihood (ML) estimation of the mean parameters. Efficiency of the sample mean over the maximum likelihood estimator (MLE) is analyzed. Spatial correlations combined with heterogeneity of spatial correlations or heterogeneity of error variances are shown to have adverse effect on efficiency of the sample mean. Therefore, in such spatially correlated and heterogeneous situations, it is recommended that spatial correlations should be properly addressed in estimating mean parameters.