Comparisons of Alternative Axial Distances for Cuboidal Regions of Central Composite Designs Using D and G Efficiencies

  • Francis Eze Nnamdi-Azikiwe University, Awka Nigeria
  • Linus Ifeanyi Onyishi Federal Polytechnic, Nasarawa
  • M. E. Nja Federal Polytechnic, Nasarawa
  • E. O. Effanga Federal Polytechnic, Nasarawa
Keywords: Axial Distances, Central Composite Design, D-Efficiency, G-Efficiency, Pythagorean Means

Abstract

In this study, three axial distances are proposed as alternatives to the existing axial distances of the Central Composite Design (CCD) in cuboidal design regions with the aim of providing formidable alternatives to the existing axial distances of the CCD whose prediction properties are less extreme and more stable in the cuboidal design regions. The three alternative axial distances, namely the arithmetic, harmonic and geometric axial distances for cuboidal regions, were developed algebraically based on the concepts of the three Pythagorean means. The strengths and weaknesses of the alternative axial distances were validated by comparing their performances with the existing axial distances in the cuboidal regions. The D- and G-efficiencies are used for comparison. The cuboidal region shows that the three alternative axial distances are consistently better in terms of the D- and G-efficiencies

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Author Biographies

Francis Eze, Nnamdi-Azikiwe University, Awka Nigeria

Department of Statistics 

Linus Ifeanyi Onyishi, Federal Polytechnic, Nasarawa

Department of Mathematics and Statistics, Federal Polytechnic, Nasarawa, Nasarawa State, Nigeria

M. E. Nja, Federal Polytechnic, Nasarawa

Department of Mathematics and Statistics, Federal Polytechnic, Nasarawa, Nasarawa State, Nigeria

E. O. Effanga, Federal Polytechnic, Nasarawa

Department of Mathematics and Statistics, Federal Polytechnic, Nasarawa, Nasarawa State, Nigeria

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Published
2019-12-18
How to Cite
Eze, F., Onyishi, L. I., Nja, M. E., & Effanga, E. O. (2019). Comparisons of Alternative Axial Distances for Cuboidal Regions of Central Composite Designs Using D and G Efficiencies. MathLAB Journal, 4, 58-66. Retrieved from https://purkh.com/index.php/mathlab/article/view/540
Section
Research Articles