Open Access Open Access  Restricted Access Subscription or Fee Access

A Measure of Rotatability for the Central Composite Designs

E. U. Ohaegbulem, P. E. Chigbu


An approach to measuring design rotatability and a measure that quantifies the percentage of rotatability in the central composite designs are introduced. This new approach is quite different from the ones provided by previous authors which assessed design rotatability by the viewing of tediously obtained contour diagrams. This new approach has no known practical limitations, and the measure has computational simplicity to its advantage.


Central composite designs, design rotatability, perfectly rotatable designs, near rotatable designs, second-order response-surface designs.

Full Text:


Disclaimer/Regarding indexing issue:

We have provided the online access of all issues and papers to the indexing agencies (as given on journal web site). It’s depend on indexing agencies when, how and what manner they can index or not. Hence, we like to inform that on the basis of earlier indexing, we can’t predict the today or future indexing policy of third party (i.e. indexing agencies) as they have right to discontinue any journal at any time without prior information to the journal. So, please neither sends any question nor expects any answer from us on the behalf of third party i.e. indexing agencies.Hence, we will not issue any certificate or letter for indexing issue. Our role is just to provide the online access to them. So we do properly this and one can visit indexing agencies website to get the authentic information. Also: DOI is paid service which provided by a third party. We never mentioned that we go for this for our any journal. However, journal have no objection if author go directly for this paid DOI service.