I have a group of n items that should ideally be homogeneous, although there may be some variability. I need to determine how many items I should sample and test to validate the entire group. I assume a standard normal distribution will fit I initially set a margin of error at 5%, with a 90% confidence level and assumed a 50% standard deviation, which resulted in a sample size of around 270 units.
Given that the group is supposed to be homogeneous and any variability is likely due to occasional errors, I am re-evaluating the parameters I used. Could anyone provide insights or suggestions to help me refine these values?
Thank you.
