According to a Virginia Tech survey, college students make anaverage of 11 cell phone calls per day. Moreover, 80% of thestudents surveyed indicated that their parents pay their cell phoneexpenses (J. Elliot, “Professor Researches Cell Phone Usage AmongStudents,” www.physorg.com, February 26, 2007).
1. If you select a student at random, what is the probabilitythat he or she makes more than 10 calls in a day? More than 15?More than 20?
2. If you select a random sample of 10 students, whatdistribution can you use to model the proportion of students whohave parents who pay their cell phone expenses?
3. Using the distribution selected in (c), what is theprobability that all 10 have parents who pay their cell phoneexpenses? At least 9? At least 8?
