An auditor samples $100$ of a firm’s travel vouchers to ascertain what percentage of the whole set of vouchers are improperly documented. What is the approximate probability that more than $30$% of the sampled vouchers are improperly documented if, in fact, only $20$% of all the vouchers are improperly documented? If you were the auditor and observed more than $30$% with improper documentation, what would you conclude about the firm’s claim that only $20$% suffered from improper documentation? Why?
I feel like I'm missing something simple in this problem. We want $P(X>.3|X=.2)$ right? Can I say that the distribution is normal?