Stochastic models

Prob.5 (a)Find the mean and variance of the random variable X if it is known that EICX 1)1 10 and EI(X - 2)21 6 (b) A company purchases several special computers at the end of each year for a project, the exact number depending on the frequency of repairs in the previous year. Suppose that the number of computers, X, that are purchased each year has the following probability distribution 2 P (X = x) 1/10 3/10 2/5 1/5 If the cost of the desired model will remain fixed at $2500 throughout this year and a discount of 50X2 dollars is credited toward any purchase, how much can the company expect to spend on the computers at the end of this year