Efficiency of modified central composite designs with fractional factorial replicates for five-variable nonstandard models

Abstract

The efficiencies of standard central composite designs are compared with modified central composite designs on non-standard models using D- and G-efficiency criteria. Diagonal elements of the Hat matrix are utilized in the construction of the modified central composite designs. Fractional factorial replicates are used to maintain manageable design sizes. Results show that D-efficiencies of the designs decline for standard CCDs as the number of missing quadratic terms increases but increase with modified CCDs for increased number of missing quadratic terms. Similarly, G-efficiencies of the designs decline for standard CCDs as the number of missing quadratic terms increases but increase with modified CCDs for increased number of missing quadratic terms.