Problem 4.5(a):
Consider Association Rule:
major (X, “science”) => status (X, “undergrad”).
(4.8)
The number of taskrelevant data tuples is 5000.
56% of undergraduates are major in science
64% of the students are undergraduate degrees
70% of the students are major in science
Compute confidence and support.
Solution:
Support= Percentage of students at university who are undergraduate students and
majoring in science.
No. of undergraduate students= 5000*0.64= 3200
No. of undergraduates in Science= 3200*0.56= 1792
Support = (1792/5000)*100= 36% (approx)
Confidence= Percentage of task relevant data tuples of the left side that also satisfy the
right side.
So, Confidence = Percentage of students who are majoring in science and are also
undergraduate students.
= 36% / 70% = 51%
[Support, Confidence] = [36%, 51%]
Problem 4.5(b):
Consider Association Rule:
major (X, “biology”) => status (X, “undergrad”) [17%, 80%]
(4.9)
Suppose that 30% of science students are majoring in Biology.
Would you consider Rule (4.9) to be novel with respect to Rule (4.8)?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '09
 Merz
 Computer Science, Academic degree, Bachelor's degree, Doctorate, Undergraduate education

Click to edit the document details