. . -. Y, - -, - . - - Y . . ov(X, Y)= M [(X MX)(Y MY)]. - - Y . .
. Y - . -, ov(X, Y)=0. : . ov(X, Y)= M [(X MX)(Y MY)]. , ov(X, Y)= M [(X Y X (MY =const) Y (MX =const)+(MXMY =const))= M (XY) MYMXMXMY+MXMY = MXMYMYMX =0, .. MC = C Y , M (XY)= MXMY M (XY) MXMY =0 ■
. . - 1 2 , D( 1+ 2)=D( 1)+D( 2) D( 1 2)=D( 1)+D( 2). : D( 1+ 2)= M [( 1+ 2 M ( 1+ 2))2] = M [ (( 1 M 1)+( 2 M 2))2]= M [ ( 1 M 1)2+2( 1 M 1) ( 2 M 2)+( 2 M 2)2]= M [ ( 1 M 1)2]+2M[( 1 M 1) ( 2 M 2)]+M[( 2 M 2)2]= D X 1+ (2 ov(X 1, X 2)=0)+ D X 2= D X 1+ D X 2■ - . - D( 1 2)= D( 1)+ D( 2) 2 ov(X 1, X 2) . - 1 2.
. - - . - X Y. - . X Y - . - - r(X, Y)=Cov(X, Y)/
. . . - Y - . . - - (X MX)(Y MY), (X MX) . - . . ( - -.), - ov(X, Y)=
. - . . . - X Y - r(X, Y)= Cov(X, Y)/
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. { = k } = , 0£ £1, q =1 p, k = 0, 1, 2,, n. ., . - X . . . . . . Sn . . n . . . , .
. : Sn = X 1+ X 2++ X n, M Sn =M X 1+M X 2++M X n. M Xk, 1 £ k £ n: M Xk =1 p +0 q = p Þ M Sn = np.
. D: Sn = X 1+ X 2++ X n, . . , D Sn =D X 1+D X 2++D X n. D Xk k =1,2 n: D Xk = M(Xk)2 (M Xk)2 = M Xk (M Xk)2 = 2 = pq. D Sn = npq.
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