38E

Solution : Step 1 : It is given that the possible values of X is the number of components in a system that submitted for repair, that must be replaced. The possible values of X and their probabilities are. X P(X) 1 .15 2 .35 3 .35 4 .15 Step 2 : a) We have to find the E(X) and E(5-X) We know that 4 1) E(X)= X × P(X) x=1 = (1*.15)+(2*.35)+(3*.35)+(4*.15) = 2.5 2) Here E(a+b)= E(a)+E(b) So E(5-X)= E(5)-E(X) = 5- 2.5 = 2.5