Non normal data is the data that do not fit into the shape of normal distribution. In fact, we are facing this type of data most of the time in the actual process.
As an engineer or manager, we should understand our process well and know what kind of distribution a particular process should behave.
Process capability calculation for non normal data isn’t straight forward as what we did for normal distributed data.
In fact, I am not so sure how to estimate the Cpk value this type of distribution manually. I still rely on Minitab when dealing with this kind of data.
I tried to search through Minitab Help and here the formula I get.
The formula looks simple, but I still can’t get a correct answer by substituting the figure I have into the equation. How come? Anyway, I need not to worry so much as Minitab can do all the statistical analysis for me.
Here the problem I have, can anybody tell me how Minitab work out the PPL = 0.4?
Last update : 18/02/07
0 comments:
Post a Comment