Explain the difference between P(relDi) and P(Direl). In the light of the Probability Ranking Principle, which of the two probabilities is of interest? Here is a set of documents containing the word cat as well as corresponding conditional probabilities: For document D1 only, calculate logP(Dinrel)P(Direl),P(relDi)/P(nnelDi) and P(relDi) assuming P( rel )=0.4. Calculate the logarithm in base 2, but explain the role that the base of the logarithm plays in the context of the Probability Ranking Principle. Tips. There is a formula in the online article on probabilistic models that is very useful for this problem. Be sure to read everything. Calculate P(relDi)aftercalculatingP(relDi)/P(nrelDi)