© 2000 Todd Neller.
A.I.M.A. t
ext
figures
© 1995 Prentice Hall.
Used by
permission.
Applying Bayes’ Rule (cont.)
•
Given:
–
P(S|M) = 0.5
–
P(M) = 1/50000
–
P(S) = 1/20
•
What's the probability that a patient with a stiff
neck has meningitis?
•
P(M|S) = P(S|M) P(M) / P(S)
•
= 0.5 * (1/50000) / (1/20)
•
= 0.5 * 20 / 50000 = 10/50000 = 1/5000
