Re: Sample size for Design Verification / Design Validation
Here's how it's been done in some of my circles. You need to identify what is critical vs "does it work as needed" (write in your own terms)...then establish what confidence level( or other criteria) you want for what you identified, ie:
Critical 95/99
Acceptable 95/95
Adequate 95/90 or 95/80
As to variable data, I have seen it done 2 ways....treat it as attribute data (in-spec-Pass/Outta spec-Fail) or evaluate to establish your confidence interval, T tests, etc..
Typically in Development, there is a push to get a design out the door, hence treating as much data as attribute data will help, but if you are also focused on making sure you can have a process that can build what you designed, make sure you work with manufacturing to develop test plans that gives them confidence that they can produce your design at higher volumes.