c) Tính \(E\left( X \right),{\rm{ }}V\left( X \right)\) và \(\sigma \left( X \right)\).
Ta có \(E\left( X \right) = 0.0,12 + 1.0,28 + 2.0,31 + 3.0,19 + 4.0,08 + 5.0,02 = 1,89\). \(\begin{array}{l}V\left( X \right) = {(0 - 1,89)^2}.0,12 + {(1 - 1,89)^2}.0,28 + {(2 - 1,89)^2}.0,31 + {(3 - 1,89)^2}.0,19 + {(4 - 1,89)^2}.0,08 + {(5 - 1,89)^2}.0,02 = 1,4379.\end{array}\) \(\sigma \left( X \right) = \sqrt {1,4379} \approx 1,1991\)