Discrete random variables

x _i - values ​​of X ,

Properties:

1) M ( C ) = C , C is a constant;

2) M ( CX ) = CM ( X );

3) M ( X ₁ + X ₂ ) = M ( X ₁ ) + M ( X ₂ ), where X ₁ , X ₂ are independent random variables;

4) M ( X ₁ X ₂ ) = M ( X ₁ ) M ( X ₂ ).

Properties:

1) D ( C ) = 0;

2) D ( CX ) = C ² D ( X );

3) D ( X ₁ + X ₂ ) = D ( X ₁ ) + D ( X ₂ ), where X ₁ , X ₂ are independent random variables.