Overview for Analyze Variability

Use Analyze Variability to analyze the standard deviations of repeat or replicate response measurements to identify factor settings that produce less variable results.

Before you can analyze the variability in your data, you must create or define a 2-level factorial design. These designs must contain repeat or replicate measurements. Then, use Pre-Process Responses for Analyze Variability to calculate and store the standard deviations.

You can also use Analyze Variability to store weights to use when examining the location effects of your response in Analyze Factorial Design. For more information, go to Analyze location effects and dispersion effects.

For example, an engineer plans to study how time, reaction temperature, and type of catalyst affect the variability of yield. The engineer creates a 2-level factorial design with 4 replicates. The engineer uses Analyze Variability to determine which factor settings produce a more consistent yield.

After you analyze the design, Minitab stores the model so that you can do the following:
  • Predict responses for different factor settings.
  • Plot the relationships between the factors and the response.
  • Find settings that optimize one or more responses.

Where to find this analysis

Stat > DOE > Factorial > Analyze Variability