Conditional Probability calcualtion In the following BBN network, what is meant by `P(Martin Late|train strike,Norman Late)`? Does this mean probability of martin Late given that Train Strike **And** Norman is Late? 2) what is meant by `P(Martin Late, Norman Late|Train Strike)`? Is this the probability that Martin **and** Norman are late, **given** the train Strike or is it probability Martin is late **and** (Norman is late given train Strike)? 3) What is `P(Martin Late=True|Norman Late=True)`? Is it `P(Martin Late=T|Train Strike=T)*P(Train Strike=T)*P(Norman Late=T|Train Strike=T)+P(Martin Late=T|Train Strike=F)*P(Train Strike=F)*P(Norman Late=T|Train Strike=F)=0.093`

1) Yes

2) the first of your two suggestions

3) No. What you have suggested is the joint probability that both Martin and Norman are late. To get the conditional probability, you would need to divide this by the probability that Norman is late, i.e. by `P(Norman Late=T)` which would be `P(Train Strike=T)*P(Norman Late=T|Train Strike=T)+P(Train Strike=F)*P(Norman Late=T|Train Strike=F)`