Setting the Control limits on Minitab

[zamshabeer]

Hello

I have a data set that I want to compare/test against locked (fixed) means and control limits.

On Minitab 19, I have the option to set the mean and standard deviation (see screenshot below). But what I want to set is the mean and control limits.

I know I can calculate the standard deviation using the 3sigma formula to get the control limits I am after, but I just wanted to check whether I can remove this extra step.

Is there a way for me to just enter the mean and control limits and then apply the tests to those fixed values?



Thanks
Best regards
Zam

 

[Miner]

I am not aware of another method than the one that you show. You can set a limit to prevent control limits from going negative, but that is all.

 

[Steve Prevette]

There is another discussion of locked (arbitrary, not based upon the data) control limits recently, and recommendations against doing that. However, I will admit Minitab does not give you much control on the calculations (such as it keeps turning the mean and control limits into moving averages as you add data). I have much better success simply using Excel spreadsheet.

 

[zamshabeer]

There is another discussion of locked (arbitrary, not based upon the data) control limits recently, and recommendations against doing that. However, I will admit Minitab does not give you much control on the calculations (such as it keeps turning the mean and control limits into moving averages as you add data). I have much better success simply using Excel spreadsheet.

Hi Steve - could you point me to that discussion if you have the link handy? This is a debate that I am trying to manage as well. Is this discussion on this website. Or somewhere else?

 

[Jim Wynne]

Hi Steve - could you point me to that discussion if you have the link handy? This is a debate that I am trying to manage as well. Is this discussion on this website. Or somewhere else?

Locking Control Limits and SPC Sample Sizes (AIAG/Automotive Requirements) (elsmar.com)