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Machine Learning and Expert system
Autumn 2014
Assignment No. 4
Q1. For the detection of breast cancer, a new test is developed. When it is
tested on a group of people, it is observed that:
a) Out of 204 patients with breast cancer,170 got positive result.
b) Out of 314 patients without breast cancer,17 got positive result.
i) What is the Sensitivity and Specificity of test?
ii) What additional information will be needed to determine whether test is
performing well or not?
iii) In patients with malignant mass, the likelihood of breast cancer is 70%.
In this case, the test result gives sensitivity of 82% and specificity of 93%.
What is the likelihood of patient with malignant mass with a positive test
result having breast cancer?
Q2. Given a function
where
where
are the variables that determine whether i-th feature is selected or
not.
Assuming maximum of function as best feature selection criteria, perform
Sequential Forward Selection.
