【六西格玛】六西格玛判异准则探讨产品质量回顾的最少批数

beiwei5du

我个人认为年度产品回顾，除了回顾批间，可能还有一点就是批内。这个应该要注意。
另一个方面如果subgroup size是1的话，可能确实要有达到一定的批次，才有意义！

https://www.spcforexcel.com/know ... late-control-limits
As mentioned before, our earlier publication said you can start an individuals control chart with as few as 5 points; recalculate the control limits with each new point and then lock the control limits in place after 20 points.  Then recalculate after 100 points.  Was that good advice?  For the most start, it is good advice.  I might change the value to 30 points to lock the limits the first time.

And, this same approach will work in determining how many samples you need for a process capability analysis.  Very often, people use 30 samples for a process capability analysis.  What is the uncertainty for 30 samples?  You now know how to determine that.

https://www.spcforexcel.com/knowledge/control-chart-basics/when-calculate-lock-and-recalculate-control-limits#how_many_points

When to Calculate, Lock, and Recalculate Control Limits

terbiumcf

是否有统计学意义