Suppose E(X) = 5 E[X(X - 1)] = 27.5 What is

  

a. E(X²)=? [Hint: E[X(X - 1)] = E[X² - X] = E(X²) - E(X)]

  

b. V(X)=?

  

c. The general relationship among the quantities E(X), E[X(X - 1)], and V(X)=?