Comparison of Different Central Composite Designs

Abstract

ABSTRACT Several measures of robustness for designs, which is considered to be optimal with respect to A-, D-, E-, and G-optimality criteria. When several designs are proposed for comparison, then their optimality properties can be compared for the choice of design. To compare a class of central composite designs on the basis of optimality, a simple characterization of the optimality may be given in terms of the eigen values of ) ( X X ′ . Trace criterion has been used to measure the effect of missing observations on the variances of the estimates of the parameters and response. The different combinations of missing observations have different effect on the variances of the estimates of the parameters. Some combinations of these observations are more informative than others. The most informative combination of missing observations increase the variance maximum as compared to a least informative combination of missing observations