The Capability Analysis option measures the conformance of a process to given specification limits. By default, capability is calculated based on a normal distribution. However, if you fit a distribution (continuous or discrete), then the capability report is produced based on that fit. To use a fit distribution, select Spec Limits or set the Spec Limits column property. When you select the Capability Analysis option for a variable, the Capability Analysis window appears. Use the window to enter specification limits, distribution type, and information about sigma.
Note: To save the specification limits to the data table as a column property, select Save > Spec Limits. When you repeat the capability analysis, the saved specification limits are automatically retrieved.
<Distribution type>
Estimates sigma (σ) using the selected methods. See Capability Analysis.
Note: There is a preference for Capability called Ppk Capability Labeling that labels the long-term capability output with Ppk labels. Open the Preference window (File > Preferences), then select Platforms > Distribution to see this preference.
Shows the values (represented by Index) of the Benchmark Z statistics. According to the AIAG Statistical Process Control manual, Z represents the number of standard deviation units from the process average to a value of interest such as an engineering specification. When used in capability assessment, Z USL is the distance to the upper specification limit and Z LSL is the distance to the lower specification limit. See Capability Analysis.
Related Information 

Help created on 9/19/2017