Understanding Basic Statistics 6th Edition by Charles Henry Brase,Corrinne Pellillo Brase

Exercise 78

Criminal Justice: Jury Duty Have you ever tried to get out of jury duty About 25% of those called will find an excuse (work, poor health, travel out of town, etc.) to avoid jury duty (Source: Bernice Kanner, Are You Normal . St. Martin's Press. New York). If 12 people are called for jury duty,
(a) what is the probability that all 12 will be available to serve on the jury
(b) what is the probability that 6 or more will not be available to serve on the jury
(c) Find the expected number of those available to serve on the jury. What is the standard deviation