Full Factorial DOE (Legacy)

When to use this tool

Use the full factorial DOE to analyze the effects of multiple factors, each at two levels, on a numerical response. These designs are best used when you have few factors (up to 4 or 5), since they can get quite large and cost prohibitive.

The advantage of full factorial designs is that they can estimate all main effects and interaction effects without aliasing (confounding with other effects).

Using EngineRoom

Use the Design Wizard to create the experimental design. The wizard offers two modes to specify the design parameters - Guide Me and Expert.

Use the Guide Me mode if you're not sure which design to use. This tool guides you through questions and answers to the best design. Use the Expert mode if you already know which design you want to use.

Example:

In this example, we will create and analyze a full factorial to reduce wait times. There are three factors being studied at two levels each:

Number of Queues: One/Two
Type of Headset: Mono-aural/Bi-aural
Extra Specialist: No/Yes

Steps:

1. Create Design:

Select Analyze > Design of Experiments > click on the Design Wizard:

Select the Guide Me mode
For the question: "Do all of your factors have 2 levels each, or do some of them have more than 2 levels?" select '2 Levels'
Click on the plus '+' sign below the two rows already displayed and enter the information on the three factors under study, then click Continue:

Select the Full design corresponding to 3 factors, which gives 8 runs:

complete the form for the design as shown below. The design will be run at two different locations (centers) so we will create two replicates of the design. Also, selecting 2 blocks will account for the variability from the replicates.

Click continue and select the design option corresponding to 2 replicates and 3 factors which gives you over 90% power to detect an effect size of 2 standard deviations.

The design summary/description is shown. Check it for any discrepancies and click Create Design:

2. Enter Data:

The design matrix opens up from the data sources panel. It contains all the information about the design, with a blank column at the end; normally you would run the experiment by following the Randomized run order, and enter the response data into this column. However, we already have the response data, so we can simply enter or copy-paste it here, after making sure the run order of both designs is identical (i.e., run #1 in the design we just created is the same as run #1 in the design table provided.) The response data provided are in Standard order, so sort the created design in the Standard order as well by clicking on the Up arrow in the Standard order column:

Copy-paste the response data into the blank column and click the Save Changes button:

3. Analyze Design:

Now it's time to analyze the design - select Analyze > Design of Experiments > DOE Analyzer.
Drag the Design matrix variable from the data sources panel onto the Design matrix drop zone on the Analyzer, and the Wait Time variable onto the Response Variable drop zone.
The output contains several parts. Click on the 'study setup' button on top right to see the effect plots: Half normal effect plot: