D
daamor
Hi all!
I've been so frustrated lately because I feel like I'm struggling with such a simple concept.
I'm used to performing design verification by choosing statistical C/ R intervals based on our risk analyses (95/90 or 95/95 usually) then selecting an attribute sample plan to test (n = 29/ 59 usually).
However, I can't for the life of me figure out how to set up the sample size for variable data collection.
Some of the specs are 2 sided. For example, lets say a pouch seal strength of 15 N +/- some number.
During Pre-DV, we may not necessarily know what our USL and LSL are yet. For most of the k-factor analysis determinations fro sample size, you have to know mean (ok lets make that 15) but standard deviation as well (how can we know this if we haven't gathered the data)?
I feel its a cart before the horse problem but I'm sure I'm missing something really critical.
1) Essentially, how do I go into a pre-DV study to collect data that will give me a statistically significant result that I can use to set specifications?
2) If we have identified specifications through other testing (challenge, etc.), and lets say we DO set the spec at 15 N +/- 1 N, how do you set up a variable sample plan at a C/R interval of 95/90 or 95/95?
Thanks in advance!
I've been so frustrated lately because I feel like I'm struggling with such a simple concept.
I'm used to performing design verification by choosing statistical C/ R intervals based on our risk analyses (95/90 or 95/95 usually) then selecting an attribute sample plan to test (n = 29/ 59 usually).
However, I can't for the life of me figure out how to set up the sample size for variable data collection.
Some of the specs are 2 sided. For example, lets say a pouch seal strength of 15 N +/- some number.
During Pre-DV, we may not necessarily know what our USL and LSL are yet. For most of the k-factor analysis determinations fro sample size, you have to know mean (ok lets make that 15) but standard deviation as well (how can we know this if we haven't gathered the data)?
I feel its a cart before the horse problem but I'm sure I'm missing something really critical.
1) Essentially, how do I go into a pre-DV study to collect data that will give me a statistically significant result that I can use to set specifications?
2) If we have identified specifications through other testing (challenge, etc.), and lets say we DO set the spec at 15 N +/- 1 N, how do you set up a variable sample plan at a C/R interval of 95/90 or 95/95?
Thanks in advance!