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Modify Design¶

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QXL DOE Tab > Modify Design

Inputs¶

Input Name, Low/High, and Type: Use to change the name of the input, the coded low and high values, and the type (Quantitative or Categorical).
Add Remove Interactions: Use to change the interactions in a design.
Change Coding Autocode/Standardize: Use to change the coding of the inputs within the X matrix. Allows the change between Autocode, standardize, and no coding.
Add/Remove Center Points: Use to add or remove center points from any design.
Modify Axial Value (CCD Only): Use to change the Alpha value within a CCD.
Change Blocking/Folding: Use to change the blocking or folding within a design.
Add/Remove Runs: Use to change the number of runs in a design.

Outputs¶

Add/Remove, Change Name/Type: Use to add or remove inputs as well as change their name and type (Quantitative, Binary, or Nominal).
Add or Remove Replicates: Use to change the number of replicates.
Generate Random Output Data: Use to fill replicates with random data. Useful when evaluating the Variance Inflation Factors (VIFs) in a design.

Replicate Format¶

Convert from Table to Stacked: Converts from Table replicates to stacked replicates. Stacked format is required for weighted regression or using sample sizes in Binary logistic regression.
Convert from Stacked to Table: Converts from stacked replicates to table format.

Randomization¶

Randomize Run Order: Randomize the sequence of runs in the design.

Autocode vs. Standardize¶

A design's coding can be changed by selecting QXL DOE Tab > Modify Design > Change Coding Autocode/Standardize.

Autocode¶

By default, Quantum XL automatically "autocodes" every input. The smallest value is coded to -1 and the largest to +1. Note: The only exception to this is a CCD in which the alpha value can exceed -1 to +1.

Example: the smallest and largest values for Input A are 20 and 40 respectively. Quantum XL will replace 20 with -1 and 40 with +1 when performing the regression.

Standardize¶

Standardization is useful when the data comes from historical sources instead of a designed experiment. If the input is highly skewed (non-symmetrical) then you may consider standardizing instead of autocoding. If you select Standardize, Quantum XL will calculate the standardized value as (Xi-Xbar)/sigma. Essentially, this places all inputs on a scale of -3 to +3.

No coding¶

No coding or standardization will be used.

Note

For most users, autocoding should always be used. Coding inputs on a scale of -1 to +1 helps with orthogonality in the interactions as well as placing all inputs on the same scale. Standardizing is also very efficient but only very advanced users should use no coding.

If, after you have reduced your model, you would like your coefficients in uncoded units, then use the uncoded regression menu item under QXL DOE Tab > Analyze Design > Uncoded Coefficients.

Add/Remove Center Points¶

Center points can be added to any experimental design by selecting QXL DOE Tab > Modify Design > Add/Remove Center Points.

Modify Axial Value¶

The number of center points and the axial value for a CCD design can be changed after the design is created by selecting QXL DOE Tab > Modify Design > Modify Axial Value.

Change Blocking and Folding¶

The blocking and folding can be changed after a design is created by selecting QXL DOE Tab > Modify Design > Change Blocking and Folding.

Add/Remove runs¶

Runs can be added or removed after a design has been created by selecting QXL DOE Tab > Modify Design > Add/Remove Runs.

Add/Remove, Change Name/Type¶

Outputs (responses) can be added or removed by selecting QXL DOE Tab > Modify Design > Add/Remove, Change Name/Type.

The name and type output (Quantitative, Binary, or Nominal) for an existing design can be changed by selecting QXL DOE Tab > Modify Design > Add/Remove, Change Name/Type.

Add/Remove Replicates¶

The number of replicates for an existing design can be changed by selecting QXL DOE Tab > Modify Design > Add/Remove Replicates.

Generate Random Output Data¶

Quantum XL will fill the replicates with random data if you select QXL DOE Tab > Modify Design > Generate Random Output Data.

Convert from Table to Stacked/Convert from Stacked to Table¶

Quantum XL will convert from Table to Stacked by selecting QXL DOE Tab > Modify Design > Convert from Table to Stacked.

Quantum XL will convert from Stacked to Table by selecting QXL DOE Tab > Modify Design > Convert from Stacked to Table.

Stacked replicate format allows weighted regression and sample sizes for binary regression.

Randomize Run Order¶

You can randomize the sequence of runs in an existing design by selecting QXL DOE Tab > Modify Design > Randomize Run Order.

Randomizing the design is considered a best practice as it removes the influence of uncontrolled variables which happened to be changing as the DOE is being executed.