Statistics Toolbox

ccdesign

Generate central composite design

Syntax

• D = ccdesign(nfactors)
  D = ccdesign(nfactors,'pname1',pvalue1,'pname2',pvalue2,...)
  [D,blk] = ccdesign(...)
  

Description

D = ccdesign(nfactors) generates a central composite design for nfactors factors. The output matrix D is n-by-nfactors, where n is the number of points in the design. Each row represents one run of the design, and it has the settings of all factors for that run. Factor values are normalized so that the cube points take values between -1 and 1.

[D,blk] = ccdesign(nfactors) requests a blocked design. The output vector blk is a vector of block numbers. Blocks are groups of runs that are to be measured under similar conditions (for example, on the same day). Blocked designs minimize the effect of between-block differences on the parameter estimates.

[...] = ccdesign(nfactors,'pname1',pvalue1,'pname2',pvalue2,...) enables you to specify additional parameters and their values. Valid parameters are:

'center'	Number of center points:
	Integer	Specific number of center points to include
	'uniform'	Number of center points is selected to give uniform precision
	'orthogonal'	Number of center points is selected to give an orthogonal design (default)
'fraction'	Fraction of full factorial for cube portion expressed as an exponent of 1/2. For example:
	0	Whole design
	1	1/2 fraction
	2	1/4 fraction
'type'	Either 'inscribed', 'circumscribed', or 'faced'
'blocksize'	Maximum number of points allowed in a block.

See Also

bbdesign, cordexch, rowexch

casewrite

cdf