Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2011.3732.3737ChigbuPolycarp E.OhaegbulemEmmanuel U.1220111122Two variations of N-point Central Composite Designs (CCDs) which are either orthogonally or rotatably restricted are compared. The basis of variation in these designs is the common distance of the axial points from the center of the design. Using the D-optimality criterion, it is concluded that replicated cubes plus one star variation is preferable to the replicated stars plus one cube variation under both restrictions.]]>Atkinson, A.C. and A.N. Donev,1992Box, G.E.P. and N.R. Draper,1982Box, G.E.P. and N.R. Draper,1987Box, G.E.P. and J.S. Hunter,1957Cochran, W.G. and G.M. Cox,1957Draper, N.R.,1982Draper, N.R. and J.A. John,1998Draper, N.R. and D.K.J. Lin,1990Fedorov, V.V.,1972Khuri, A.I.,1988Montgomery, D.C.,1991Myers, R.H.,1991Nalimov, V.V., T.I. Golikova and N.G. Mikeshina,1970Nwobi, F.N., A.C. Okoroafor and I.B. Onukogu,2001Onukogu, I.B.,1997Pazman, A.,1986