A hospital is hoping to introduce a Fast Care Unit. The hospital finds that after the initial run, 75% of the patients were pleased with the service. We ask 15 randomly selected patients whether or not they are pleased with the service.
(a) Is this a binomial experiment? Explain how you know.
(b) Use the correct formula to find the probability that, out of 15 patients, exactly 11 are pleased with the service. Show your calculations or explain how you found the probability.