Americans spend over $30 billion dollars on a variety of weight-loss products and services. In a study of retention rates of those using the Platinum Program at Jenny Craig from May 2001 to May 2002, it was found that about 25% of those who began the program dropped out in the first four weeks.7 Assume that we have a random sample of 300 people who are beginning the program.
(a) What is the mean number of people who will drop out of the Platinum Program in the first four weeks in a sample of this size? What is the standard deviation?
(b) What is the approximate probability that at least 210 people in the sample will still be in the Platinum Program after the first four weeks?