Hello everybody,
I would like to get some feedback from the ocmmunity - most likely somebody was solving a similar problem at some point.
I have a set of measurements/corrections that are done more or less at set intervals on number of tools. We see that the measurements are not very far from each other each time for one category of measurements and we would like to extend the lifetime of each measurement, so the intervals between measurements are longer. In other words we want to prove that it is still safe to some degree NOT to do those measurements as often.
So far what we want to do is to set 2 sigma control limits for the data set and then for each tool and for each point calculate time it needs to hit the first OOC point. Then just take interval right before that so that 95% of all points would have been measured BEFORE they hit OOC.
Does that sound reasonable? Or there are some other methods to determine this "lifetime" and numerically prove that it is safe to extend the "lifetime" of this measurement?
Any ideas would be highly appreciated.
Thanks,
M.
