I did not find quite this question searching here and on Google, which probably means I do not know the correct terminology.
Looking for a general formulation of the probability of a certain number of parts out of a lot being good given a certain failure rate. For instance, if I have $n$ parts, and each has a $Y$ probability of being defective. What are the odds that $k$ of them won't be defective, (with $k \le n$ of course!) . I thought about it some and looked at some general combinatorics explanations, but that learning is too far in my past for me to puzzle it out quickly.
Thanks!