There are different ways to do this depending on which control chart platform you are running: With the Analyze>Quality and Process>Control Chart>Xbar Control Chart, simply change the subgroup size in the Constant Subgroup Size box (default is 5)
![Screen Shot 2022-06-13 at 12.12.04 PM.jpg Screen Shot 2022-06-13 at 12.12.04 PM.jpg](https://community.jmp.com/t5/image/serverpage/image-id/43229i7D0401A238786D15/image-size/medium?v=v2&px=400)
In the Analyze>Quality and Process>Legacy Control Charts>Xbar, there is a similar option Sample Size Constant:
![Screen Shot 2022-06-13 at 12.15.04 PM.jpg Screen Shot 2022-06-13 at 12.15.04 PM.jpg](https://community.jmp.com/t5/image/serverpage/image-id/43231i40E94F94A5B1910D/image-size/medium?v=v2&px=400)
"All models are wrong, some are useful" G.E.P. Box