Is the documentation for INCLUDING CATEGORICAL FACTORS in the Statistics Toolbox correct?

The documentation mentions the following:

 In this example we have three categorical factors, each taking three levels. We create a candidate set F containing all 27 combinations of these factor levels. Then we create a matrix C containing dummy variables for the factors, and we remove enough columns to make the resulting matrix full rank. (We remove one column for each factor except the first factor.) Finally, we use the candexch function to generate a 9-run design. The resulting design has the property that for each pair of factors, each of the 9 possible combinations of levels appears exactly once.

 The above documentation potentially implies that in the resulting design, all the possible combinations are unique. Is this correct?

Answer 1

[MathWorks Support Team]

This bug has been fixed in Release 14 Service Pack 2 (R14SP2). For previous releases, please read below for any possible workarounds:

This is an error within the documentation for Statistics Toolbox. The example in the documentation happens to result in unique combinations of the factor levels. However, this unique combination of factor levels need not be true for all cases. Our documentation staff will correct this in a future release of the Statistics Toolbox