LING / C SC 439/539 Written Assignment #4 Due Wednesday 2/27

brewerobstructionAI and Robotics

Nov 7, 2013 (3 years and 11 months ago)

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LING / C SC 439/539



Written Assignment #4



Due
Wednesday 2/27

Submission instructions: put answers on a sheet of paper (may be typed or hand
-
written) and turn in
during class or place under the door of Douglass 305, on or before the due date.
Written
assignments
may not be turned in through e
-
mail
.


1.

Bayes rule


Chad is sad from his recent divorce. He decides to call in sick and spend the day
eating chocolates
and
watching videos of his wedding ceremony. He has 3 boxes of choc
o
lates. Box #1 has 20 plain

chocolates and 10 with nuts; box #2 has 10 plain and 10 with nuts; box #3 has 30 pieces with nuts.
Chad cares so little about life that, even though he doesn't like nuts, he is randomly grabbing
chocolates from the three boxes
one at a time
and eating the
m. The three boxes have different
sizes, so the chances of Chad selecting from box #1, #2, and #3 are 2/9, 3/9, and 4/9, respectively. If
Chad
eats
a
piece of
chocolate with nuts, what is the probability that he picked it out of box #2?

Solve using Bayes r
ule.



2.

Inference in Bayesian networks


What is the probability that there was neither a burglary nor an earthquake, given that John didn’t
call? Calculate the answer through

marginalization of joint probabilities.


Hint: the answer contains the digits 3 a
nd 7

at these positions:

0.
XXX3X
7
XXX…