a. Assume the online test has 15 multiple questions. Each question has five possible answers, of which only one is correct.

i. What is the probability that guesswork will yield at least seven correct answers?

ii. What is the expected number of correct answers by guesswork?

b. At Delta limited the Chief Administrative Manager analyzed the number of incoming faxes. After

an analysis, the manager determined the probability distribution of the number of pages per fax as follows:

x

1

2

3

4

5

6

7

P(x)

0.05

0.12

0.2

0.3

0.15

0.1

0.08

Required:

Compute the mean and the variance of the number of pages per fax.