Hypothesis testing is useful in medicine because it is helpful in determining whether or

Hypothesis testing is useful in medicine because it is helpful in determining whether or not a drug is actually effective. Let’s say 100 people took the drug, and 7 of them showed positive effect. Is that enough people to warrant the drug is effective? What about twelve of them? 15 of them?50 of them?All 100 of them? 

How might one go about the hypothesis test for the drug effectiveness example cited?