7.17 There are four classes of insureds, each of whom may have zero or one claim, with the following probabilities: Number of claims Class 1 A 0.9 0.1 0.2 B 0.8 0.5 0.5 0.1 0.9 A class is selected randomly, with probability of one-fourth, and four insureds are selected at random from the class. The total number of claims is two. If five insureds are selected at random from the same class, determine the Bhlmann- Straub credibility estimate of the expected total number of claims.