In fact, most people will come to this step to do Normal Capability Analysis without checking the statistical assumptions ( stability and Normality )
Most will use Microsoft Excel worksheet to calculate Cp & Cpk but seldom will calculate Pp & Ppk due to limitation of data collection.
The formula for Cp, Cpk, Pp & Ppk are as below :
In Minitab, Cp, Cpk, Pp & Ppk can be calculated easily.
E.g. Sample data is collected as follows :
Using Minitab software, arrange above as data structure as shown on Minitab worksheet below
Then, go to Stat>Quality Tools>Capability Analysis>Normal to run the analysis
The results of Capability Analysis as follows :
What’s your take on that ?