What’s A Bartlett’s Test?

Bartlett’s Test is a hypothesis test that determines whether a statistically significant difference exists between the variances of two or more independent sets of normally distributed continuous data. It is useful for determining if a particular strata or group could provide insight into the root cause of process issues.

An example would be if Assembly Line A product weights have a variance of 1 gram, Assembly Line B product weights have a variance of 2 grams and Assembly Line C product weights have variance of 2.5 grams and you want to determine if any of the 3 lines truly has less/more variation than the others or if the difference is just due to random chance

Learn more about Bartlett’s Tests in Analyze Phase, Module 4.3.2 of Black Belt Training.

How To Run A Bartlett’s Test In SigmaXL

Download the GoLeanSixSigma.com Bartlett’s Test Data Set for SigmaXL here.

1. Highlight the Data:

Bartlett'sTest-SigmaXL-RawData

2. Go to Statistical Tools >Equal Variance Test > Bartlett:

Bartlett'sTest-SigmaXL-Select

3. Click Next:

Bartlett'sTest-SigmaXL-Settings

4. Select Fill Levels. Then click once on Numeric Data Variable to enter it into the tab.

5. Select Sauce Type. Then click once on Group Category to enter it into the tab.

6. Click OK:

Bartlett'sTest-SigmaXL

To learn more about Bartlett’s Tests, register for Black Belt Training and review Analyze Phase, Module 4.3.2.