I am working in JMP 15. And I cannot save the control limits for a P Chart that I generated, because the UCL is different for each "Y."
I need to be able to save the limits for each Y attribute. Is this only possible for I Charts when the UCL is constant?
Sorry. I forgot that you had an attribute chart. Show Sigma Report is only available for Variables control charts. Control chart builder has no method of specifying non-constant limits for attribute charts. This can be done with variables charts only.
I'm not exactly sure what you mean by "for each Y"? Do you mean for each sample or are you asking about different reasons for failure? I think you understand the issue, p-charts will have varying control limits because the size of the sample is changing. If you can keep the sample size constant (np charts) then you could get a constant control limit. I MR charts may be useful depending on the proportion of defectives (large proportions).
If you use the Save Summaries option in the red triangle menu, you can see the varying control limits for each point plotted.
Thank you Tonya, this worked. Now my question problem is - how do I apply those limits to a different chart. I used the "Get Limits" function. But I got this error:
This was when I tried to use the data table directly in the format that was put out by "Save Summaries"
The summary data table does not have the proper format for a limits data table. Furthermore, a limits data table only works if the limits are constant. It does not work with non-constant limits. You will need to grab the sigma from the Show Sigma report and then use JSL similar to the following
Control Chart Builder(
Variables( Y( :NO ), Subgroup( :State ) ),
Chart(
Position( 1 ),
Set Control Limits( {Avg( 0.026 ), Sigma( 0.02 )} ),
),
Chart(
Position( 2 ),
Set Control Limits( {Avg( 0.02 ), Sigma( 0.0241124109987879 )} )
)
)
Do you have any idea why the Show Sigma Report would be greyed out, not allowing me to click?
Sorry. I forgot that you had an attribute chart. Show Sigma Report is only available for Variables control charts. Control chart builder has no method of specifying non-constant limits for attribute charts. This can be done with variables charts only.