Varying spec limits by data category in variability chart
Feb 8, 2024 04:17 PM(39845 views)
Hi,
I have an application where I use a variability chart in JMP Pro 14 to represent data collected at discrete intervals over some time period. Based on this data collection, the spec limits on the data will also need to be varied. For example:
During "Phase K" of a project there might be M different sample groups each with its own sample size N. During Phase K, there will be some set of limits which we'll want to plot against this.
At some point, the project will enter "Phase K+1" during which we will adjust the spec limits and collect additional data which will need to be compared to the new limits.
Repeat ad-nauseum...
Is there a way to code spec limits to a continuous numeric column which are controlled by a separate column in which the project phase is encoded such that when I plot the data in the Y of a variability chart, the chart will include the appropriate spec limits in the variability chart for each of the sample groups? I'm okay doing something as crude as creating LSL/Target/USL columns directly in the table, but of course that isn't preferred.
By the way, I'm aware that variability charts may not be the "correct" way to represent this data, but it's what's done, so here we are