Advantages and disadvantages of
The CF formalism has been quite popular with expert
system developers since its creation because
1. It is a simple computational model that permits
experts to estimate their condence in conclusion
The probability of an event A, given B occurred, is called
a conditional probability and indicated by
P(A | B)
The conditional probability is dened as
P(A n B)
P(A | B) = ---------------- --, for P(B) :5 0.
Hypothetical reasoning and
0 Bayes Theorem is commonly used for decision tree
analysis of business and the social sciences.
o The method of Bayesian decision making is also used
in expert system PROSPECTOR.
We use oil exploration in
Calculation with Certainty Factors
Although the original denition of CF was
CF = MB - MD
there were difculties with this denition
0 because one piece of disconrming evidence could
control the conrmation of many other pieces of
For example, te