What’s Design Of Experiments (DOE) – One Factor At A Time (OFAT)?

DOE, or Design of Experiments is an active method of manipulating a process as opposed to passively observing a process.  DOE enables operators to evaluate the changes occurring in the output (Y Response,) of a process while changing one or more inputs (X Factors).

Learn more about Design Of Experiments (DOE) – One Factor At A Time (OFAT) in Improve Phase, Module 5.1.1 of Black Belt Training.

How To Run A Design Of Experiments (DOE) – One Factor At A Time (OFAT) In SigmaXL

Download the GoLeanSixSigma.com Design Of Experiments (DOE) – One Factor At A Time (OFAT) Data Set for SigmaXL here.

In this 1 factor experiment we are testing the impact of changing the packaging in an effort to improve packaging time. We have data on the packaging time prior to the change (Avg. Pack. Time) and have collected data after changing the packaging (Experiment Results).

DOE-OFAT-SigmaXL-RawData

The difference in time looks substantial, but we will go ahead and run a statistical test (in this case a 2 sample t test)

1. Go to SigmaXL>Statistical Tools>2 Sample t-Test:

DOE-OFAT-SigmaXL-Menu

2. After you identify which columns contain our data, click on Next >>

DOE-OFAT-SigmaXL-SelectData

3. Click on Numeric Data Variables (Y) >> 2 times then click OK:

DOE-OFAT-SigmaXL-Variables

4. The results will show up in a new tab (shown at the bottom of the spreadsheet):

DOE-OFAT-SigmaXL

The results show a p value of zero (in reality some very small number like .00000001) so we reject the Null Hypotheses and accept that the new packaging (with an average time of 1.983 min.) is better than our old packaging (with an average time of 7.034 min.).

Learn more about Design Of Experiments (DOE) – One Factor At A Time (OFAT) in Improve Phase, Module 5.1.1 of Black Belt Training.