Chapter 6, Problem 46SE

The time (in minutes) between telephone calls at an insurance claims office has the following exponential probability distribution.

$f(x)=.50e^{-.50x}\text{ for }x\ge 0$

1. a. What is the mean time between telephone calls?
2. b. What is the probability of having 30 seconds or less between telephone calls?
3. c. what is the probability of having 1 minute or less between telephone calls?
4. d. what is the probability of having 5 or more minutes without a telephone call?