Exercise 1.
About 15% of the population is left-handed. Use the normal distribution to
approximate the probability that in a class of 150 students,
(a) at least 25 of them are left-handed.
(b) between 15 and 20 are left-handed.
Exercise 2.
Suppose the life of a Uphone has exponential distribution with mean life of 4 years. Let X denote the life of a Uphone (or time until it dies). Given that the Uphone has lasted 3 years, what is the probability that it will 5 more years.
Research and Lecture notes 