Hi Sir Thanks a lot for detailed explanation One small clarification or request i have is to throw some light on minimum sample size calculation when there is low population For example we are producing only 50 or 100 parts and want to know how many samples are necessary to quantify process capabilities? Suppose we dont have any previous knowledge of the scatter or mean Most of examples show it for success or failure based samples or they show for normal distribution given that we know scatter about process to being with But if we dont havw any details how do we know what number of samples are enough to quantify that
Good question! If you have low sample sizes, say 50-100, you should be ok to calculate Process capability after checking for normal distribution. Basically the standard deviation values stabilize with 40-50+ sample size. If you use Minitab, it shows a confidence interval for Cpk value. Also, for small sample sizes, 1.5 Sigma shift will not apply! Hope this helps.
Thank You So Much Sir, for your detailed lucid explantion
Welcome! My pleasure! 🙏
Welcome! My pleasure! 🙏
Hi Sir
Thanks a lot for detailed explanation
One small clarification or request i have is to throw some light on minimum sample size calculation when there is low population
For example we are producing only 50 or 100 parts and want to know how many samples are necessary to quantify process capabilities?
Suppose we dont have any previous knowledge of the scatter or mean
Most of examples show it for success or failure based samples or they show for normal distribution given that we know scatter about process to being with
But if we dont havw any details how do we know what number of samples are enough to quantify that
Good question! If you have low sample sizes, say 50-100, you should be ok to calculate Process capability after checking for normal distribution. Basically the standard deviation values stabilize with 40-50+ sample size. If you use Minitab, it shows a confidence interval for Cpk value. Also, for small sample sizes, 1.5 Sigma shift will not apply! Hope this helps.