Analyze Factorial Design

General Full Factorial Designs - Table of Means

Minitab displays fitted means for the factors included in the model. Fitted means are the means for each factor level or combination of factor levels that you can expect to get if your design is balanced.

Example Output

Means

Fitted

Term Mean SE Mean

ExCoat

None 6.5167 0.0559

Paint 6.7167 0.0559

Plastic 6.9833 0.0559

Alloy

A 6.6667 0.0559

B 6.6167 0.0559

C 6.9333 0.0559

ExCoat*Alloy

None A 6.5000 0.0968

None B 6.3500 0.0968

None C 6.7000 0.0968

Paint A 6.7000 0.0968

Paint B 6.5000 0.0968

Paint C 6.9500 0.0968

Plastic A 6.8000 0.0968

Plastic B 7.0000 0.0968

Plastic C 7.1500 0.0968

Interpretation

The table below, for the metal part data, may help you visualize the results.

ExCoat
Alloy	None	Paint	Plastic	All
A	6.5000	6.7000	6.8000	6.6667
B	6.3500	6.5000	7.0000	6.6167
C	6.7000	6.9500	7.1500	6.9333
All	6.5167	6.7167	6.9833

For example:

· When there is no exterior coating (ExCoat = None) applied to the metal part, the mean corrosion resistance is 6.5167.

· When the alloy type is A, the mean corrosion resistance is 6.6667.

· When the exterior coating is paint and the alloy type is B, the mean corrosion resistance is 6.5000.

The analysis of variance table showed significant effects for both exterior coating and alloy. You can see by the table means that:

· plastic coated parts had the highest corrosion resistance followed by paint. Parts with no coating showed the least resistance.

· Alloy C had the highest corrosion resistance followed by Alloy A. Alloy B showed the least resistance.