Menu.ccdTab1 {RcmdrPlugin.DoE}R Documentation

Basic information for Central Composite Designs

Description

Basic information for Box-Behnken designs

Brief statistical background

Central composite designs can have three (alpha=1) or five levels in all factors and are useful for fitting second order polynomials to experimental data based on several quantitative response variables. They can be used in a process of sequential experimentation, experimenting first with the cube portion and later adding (a) star block(s).

For more information, look at the help file for function ccd.design from package DoE.wrapper or at ccd from package rsm.

Inputs on Tab Base Settings

name of design
must be a valid name. The design itself is created under this name in the R workspace.
Determine the cube portion
An existing 2-level fractional factorial, preferrably of at least resolution V, can be selected, or a new design for the cube portion can be generated.
number of center points
refers to the center points in the star portion. The number of center points in the cube portion is defined within the cube itself.
alpha
determines how far inside (alpha<1) or outside (alpha>1) of the cube the star points are positioned. The special values orthogonal (default) or rotatable define calculated alpha values with interesting statistical properties. However, it must of course be checked whether these make practical sense. For example, if the orthogonal alpha turns out to be 2 but experimentation beyond 1.5 does not make sense, the number should be defined manually.
seed
can be provided for reproducing an existing design.
randomization
can be switched off in exceptional situations. Usually, one would not want to do that. Note that the checkbox here refers to the star portion only. For the cube portion, there is also such a checkbox.

Author(s)

Ulrike Groemping

References

~put references to the literature/web site here ~

See Also

See also FrF2 for the function defining the cube portion of the design ccd.augment for the function that augments the cube portion with the star points, also function ccd from package rsm for the function that underlies function ccd.augment.


[Package RcmdrPlugin.DoE version 0.6-10 Index]