Lab results indicate that a certain drug is effective 75% of the time (success) and ineffective 25% of the time (failure). As a trial, the drug is administered to a sample of 1000 patients. a. (6 marks) What is the probability that between 710 and 770 of the patients are helped by the drug? (Remember to think in terms of proportion: i.e. 710 is what proportion of the 1000 tested? 770 is what proportion of the 1000 tested?)
b. (3 marks) What is the probability that at least 770 of the patients are helped by the drug?