Distributions Help

SPC for Excel performs a normal probability plot to determine if you data is normally distributed.

SPC for Excel features data transformation (to transform data to a normal distribution) and distribution fitting.  The data transformation includes:

• Box-Cox Transformation
• Johnson Transformation

SPC for Excel fits the following distributions:

• Exponential
• Exponential – Two Parameter
• Gamma
• Gamma – Three Parameter
• Largest Extreme Value
• Logistic
• LogLogistic
• LogLogistic – Three Parameter
• LogNormal
• LogNormal – Three Parameter
• Normal
• Smallest Extreme Value
• Weibull
• Weibull – Three Parameter

The distributions are defined by one or more of four parameters:

• Location
• Shape 
• Scale
• Threshold

These features are accessed through the “Distributions” panel on the SPC for Excel ribbon.

The links below provide more information:

• Normal Probability Plot with Anderson-Darling Statistic
• Data Transformation
• Distribution Fitting