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Custom Designs How-To

This walkthrough builds a design sheet from run settings you supply yourself, and then shows the one extra question the first analysis on it asks.

Use this when the runs are already decided: a design somebody else specified, a set of conditions the process allows, or an experiment already performed whose results you want analysed.

Sample Data

An experiment that has already been run: sixteen sets of settings with the response measured at each. This is the data every DOE walkthrough in this section uses, and a custom design is how data collected outside Quantum XL gets analysed.

Press Copy for Excel, then paste the table into a blank worksheet.

Temp Press Time Strength
180 40 10 49.5
220 40 10 65.4
180 60 10 61.8
220 60 10 66.8
180 40 20 52.3
220 40 20 70.7
180 60 20 60.7
220 60 20 70
180 40 10 50.6
220 40 10 66.4
180 60 10 61.2
220 60 10 67.2
180 40 20 51.4
220 40 20 67.1
180 60 20 61.9
220 60 20 71.6

Click cell A1 and press Ctrl+V. The header row lands in row 1 and the 16 runs in rows 2 through 17, ready to be copied into the design sheet the steps below build.

Temp is in degrees C, Press in psi and Time in seconds, and Strength is the peel strength of the finished bond. Each of the eight setting combinations was run twice.

Steps

  1. QXL DOE New > Create Design, choose Custom Design, press Next.

  2. Set the number of factors to 3 and the number of runs to 16. Name the factors Temp, Press and Time.

  3. Name one output Strength and press Finish.

  4. Copy the four columns into the sheet. The three factor columns take Temp, Press and Time, and the output column takes Strength. The cells you are meant to fill are the ones left unprotected.

What you get

An empty design sheet sized to what you asked for, with a column per factor, a column per output and a row per run. Nothing is generated: the run settings are yours to type in.

The sheet is protected, as every Quantum XL design sheet is, so the structure cannot be edited away by accident. The cells you are meant to fill are the ones left unprotected.

The first analysis asks what the sheet does not say

A generated design records how it was built. A custom design cannot. So the first time you run a regression on it, Quantum XL asks for the information it needs and no generator supplied, and it stores your answer on the sheet so it is asked once and not again.

That page is described on Custom Designs.

Things to try next

  • Type your runs in and run a regression. The extra question appears, and the second regression on the same sheet does not ask again.
  • Ask for more runs than you need. Rows left empty are excluded from the fit rather than treated as zeros.
  • Compare it with a generated design. A generated sheet arrives with its runs already written and its build recorded, which is why it never asks the extra question.

See Also