STAT 408
Spring 2009
Version B
Name _________________________
Section __________
Quiz 2
(10 points)
Be sure to show all your work; your partial credit might depend on it.
No credit will be given without supporting work.
1.
A local meteorologist noticed that if it rains on Monday, then the probability that
it also rains on Tuesday is 0.60. However, if it does not rain on Monday, then the
probability that it rains on Tuesday is only 0.20. Suppose that the probability that
it rains on Monday is 0.25.
a) (4) What is the probability that it rains on Tuesday?
Answer: __________.
b) (2) Suppose one week it rained on Tuesday. What is the probability that it also
rained on Monday?
Answer: __________.
