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Create Custom Design¶

QXL DOE New > Create Design > Special > Create Custom Design

QXL DOE New > Create Design > Special > Setup Historical Analysis

Both of those menu entries open the same dialog and produce the same result. A custom design is an empty design sheet of the size you ask for, which you then fill in yourself, so it is also how data that was collected outside Quantum XL gets analysed.

Setup Historical Analysis is a second door into this dialog

It has behaved this way since version 17. There is no separate historical analysis capability in Quantum XL, and nothing about the design that gets created differs between the two menu entries.

The dialog¶

Two pages.

This dialog carries no page titles, so the pages are identified by their controls:

Page	What it asks
first	Select number of factors in the design, a list of 1 to 100 opening at 3, and Enter number of runs:, a list of 1 to 100 then 200, 300 and so on to 1000, opening at 8. Both accept a typed value
second	Select number of outputs:, and the Design format choice of Stacked or Table

Next on the first page becomes Finish on the second. The window's own caption is Create Custom Design.

Both numbers are bounded by the worksheet, not just by the lists. A non-numeric entry gives Number of runs must be numeric. Too many factors gives Number of variables is too big for the Excel worksheet. Use value less than n. and too many runs gives Number of runs is too big for the Excel worksheet. Use value less than n.

What you get¶

A worksheet with the right number of factor columns and run rows and nothing in them. Up to 26 factors the columns are named A, B, C and so on; past 26 they are named F1, F2, F3. The sheet carries its instructions in grey text, pointing at the cells they refer to: <-- enter factor names means those headings are yours to overwrite.

Type in the factor names, the settings each run used, and the response data. Nothing is validated until you run something against it.

The first analysis asks for what the sheet does not say¶

A design created by any other command already knows what kind of factor each column is, because you told the builder. A custom design does not, so the first time you run a regression, run Optimize, or open Modify Design, Quantum XL asks for the missing information and then stores your answers in the sheet so it never asks again.

Two pages of questions:

The type of each factor. One row per factor showing its coded name and its name, with a Type: list offering Quantitative or Categorical, and Is nested within factor: with the factor it is nested in.
The interactions to include. The interaction editor, with Interactions available on one side and Interactions in model on the other. Drag between the lists or use Add >> and << Remove. Degrees of freedom remaining: n updates as you add terms, because a custom design has a fixed number of runs and every term spends one.

Interactions can be added in groups: the available list holds nodes for Quadratic, Custom and n - way interactions, and adding the node adds everything under it.

Nesting¶

Is nested within factor: marks a factor whose levels only mean something inside another factor's level. Nesting is checked before the other model rules and the software treats a nesting violation as critical, so a model that breaks it is rejected rather than warned about.

It is a checkbox, and it is not always available. It stays disabled unless at least one other factor in the list is Categorical, so a design whose factors are all quantitative cannot nest anything. Tick it and a list appears offering none plus the categorical factors only: a quantitative factor can never be the parent.

Design sheets are protected¶

Quantum XL protects the design worksheet and unprotects it only to write to it. If protection cannot be removed, the command stops with Design sheet cannot be unprotected. rather than writing a partial result.