I have a test that I use, but was hoping for a more simple formula. If you have one can you please post it? And also I'm sorry that I have not been online much as of late.
I have a whole bunch of them, typically at least 5 of each sub-primal (to get a good average) for each of 2-4 ways to merchandise them. Problem is they are on 5 1/4" floppies in SuperCalc (predecessor to Excel) format. I would not be surprised that my old Osborne-1 CP/M computer booted up still, but not sure how I now could get them to another PC. I don't think I have any of my old dial up modems around any more.