All of the following are TRUE about Certainty Factors (CFS) except for The combination of CF's for all rules must add up to 100% CFs are not the same as a probability O CFs of 2 rules R1 and can be combined as CF(R1,R2) = CF(R1) + CF(R2)[1 - CF(R1)] CFs of 2 rules R1 and R2 can be combined as CF(R1,R2) = CF(R1) + CF(R2) - CF(R1) * CF(R2) = + CFs show a measure of belief in something