CS 484 - Artificial Intelligence
Fall 2005

Loyola College > Department of Computer Science > CS 484 > Homework > Homework 9
1) Suppose one is intereted in a rare syntactic construction, perhaps parasitic gaps, which occurs on average once in 100,000 sentences. Joe Linguist has developed a complicated pattern matcher that attemps to identify sentences with parasitic gaps. It's pretty good, but it's not perfect: if a sentence has a parasitic gap, it will say so with probability 0.95, if it doesn't, it will wrongly say it does with probability 0.005. Suppose the test says that a sentence contains a parasitic gap. What is the probability that this is true? (Use the witness reliability problem as an model. You'll have to calculate the prior probability of the pattern matcher identifying a sentence as one containing a parasitic gap.)

2) Compute the probability of the event 'A period occurs after a three-letter word and this period indicates an abbreviation (not an end-of-sentence marker),' assuming the following probabilities.

3) Create a naive bayes classifier from the movie data on page 279. Using the m-estimate, classify films 11 and 12 on page 288. Which of these classfications agree with the decision tree on page 277 about whether the films will be a success at the box-office? Let m = 5.