12. Suppose the time spent by a randomly selected student at a campus computer lab has a gammadistribution with mean 20 and variance 80 minutes^2. What are the values of and ?

a. = 20, = 80 b. = 5, = 4 c. = 1/20, = 1/80 d. = 10, = 2 e. None of the above.

13. Let X denote the distance an animal moves from its birth site to the first territorial vacancy it encounters.Suppose that X has an exponential distribution with parameter = 0.024. What is the probabilitythat the distance is at most 150m?

a. 0.9728 b. 0.0272 c. 0.0007 d. 0.024 e. None of these above.1

4. A continuous random variable may assume

a. any value in an interval or collection of intervals

b. only integer values in an interval or collection of intervals

c. only fractional values in an interval or collection of intervals

d. only the positive integer values in an intervale. none of these

15. A description of the distribution of the values of a random variable and their associated probabilities iscalled a

a. probability distribution b. random variance c. random variable d. expected value e. none of these