Hi there im looking for a formula to decide if my sample size if good enough.
- I have population of 2 million items.
- I selected 50000 of them at random and I checked that they all are correct.
- Any item out of the population may be correct or incorrect (i am searching for defects).
- I do not know what is the probability of items being correct / faulty.
How do I figure out what is the probability that there is less than 10, 100, 1000 defects? If i want to have 99.9% confidence that there is less than 100 defects in the population of 2mln, how do i calculate the sample size?
Thanks a lot for help :)