Name:________________________________________
1. In a group of 35 people, what is the probability that at least two people have the same birthday?
2. A jar has 12 green jellybeans and 9 red jellybeans. Suppose 6 jellybeans are selected at random,
without replacement, from the jar. What is the probability that in the sample
a) All of the jellybeans are green?
b) There are three green and three red jellybeans?
c) There are at least 5 green jellybeans?
3. On the basis of his sale records, a salesman knows that his weekly commissions have the following
probabilities.
Commission
Probability
0
$1,000.00
$2,000.00
$3,000.00
$4,000.00
0.15
0.2
0.45
0.1
0.1
Find the salesman's expected commission.
4. The Black Gold Oil Co. is considering drilling either in Jed's back yard or his front yard. After testing,
they estimate that there is a 30% chance of striking oil in the back yard and a 40% chance in the front yard.
They also estimate that the back yard site would either net $60 million (if oil is found) or lose $6 million (if
oil is not found), and the front yard site would either net $40 million or lose $6 million.
a) Find the expected value of drilling in the front yard.
b) Find the expected value of drilling in the back yard.
c) Where should they drill?