STAT 285 - Assignment III
Due Date: July 28th
, 2025
Question 1
An academic department with four faculty members must select two of its members to serve on a personnel
review committee. The last names of the four faculty members are Anderson, Box, Cox and Cramer. Being on
the committee is time-consuming and no one wishes to volunteer, so instead they decide to do it randomly.
Each member writes their names on slips of paper, they all put them in a hat and then two slips are drawn
without replacement. Whoever’s names are on those two slips gets assigned the job.
a) List all the possible outcomes. – 1.5 pts
For the remaining parts, assume all the outcomes listed in part (a) are equally likely.
b) What is the probability both Anderson and Box are selected? – ¼ pt
c) What is the probability Cramer is selected? – ¼ pt
d) What is the probability that at least one of the two members whose last name begins with C is
selected? – ½ pt
Question 2
Consider randomly selecting a student at Universal University, and let V denote the event that the selected
individual has a Visa credit card and M be the analogous event for a MasterCard. Suppose that Pr(V) = 0.5,
Pr(M) = 0.4 and Pr(V M) = 0.25.
a) Describe, in terms of V, M and set operations, the event that the selected student has at least one of
the two types of credit cards and then calculate its probability. – ¾ pt
b) Describe, in terms of V, M and set operations, the event that the selected student has neither type of
credit card and then calculate its probability. – ¾ pt
c) Describe, in terms of V, M and set operations, the event that the selected student has a Visa card but
not a MasterCard, and then calculate its probability. – 1 pt
Question 3
Suppose we are given two events, A and B, with Pr(A) = 0.6 and Pr(B) = 0.22.
a) Suppose A and B are independent, find Pr(A B). – ¾ pt
b) Instead of assuming A and B are independent, assume they are mutually exclusive,
find Pr(A B). – ¾ pt
c) Again, suppose A and B are mutually exclusive, find P(A|B). – ½ pt
d) Can the above events, A and B, be both independent and mutually exclusive from each other?
Explain why or why not. – ½ pt