. ()>0. - , . , - , - ( \ )=()/(). () = ( \ )() . - (. () = 0).
. ( -) n ³ 2 : ( 1 2 n) = ( 1)( 2\ 1)( 3\ 1 2) ( n\ 1 2 n-1). : . n = 2 3, n = N ³ 3. , . n = N +1. . ( 1 2 n n+1) = ( 1 2 n)( n+1\ 1 2 n)= (1)(2\1) ( n\ 1 2 n-1)( n+1\ 1 2 n)■
. ( -) . ( + ) = () + () (). : , . -: + = + ( \ ) [ Û U(+)], ( \ ) = Ø [ Û ∩()]. - [ ( + ) = ()+(), = Ø ] ( + ) = ( + ( \ )) = () + ( \ ). ..( \ ) = () (), ( + ) = () + () () ■
, . .
.
1, 2n 1, 2n = Ω
AiAj = Ǿ, i ≠j
,
Ai { 1, 2n } P(B) = =1∑n(k)* (/k) ( = 1..n)
-:
=A*Ω = (1+2+n) ==1∑n P(k)
BAi*Baj = Ǿ, i ≠j
P(B)= =1∑n P(k)= =1∑n P(Ak)* P(/k),
(P(AB)=P(A)*P(B/A))
.
(N-M) 2 ,
, 2- :
:
. 1, 2,
1 ={1- }
2 ={1- }
={2- }
:
P(B) = P(A1)*P(B/A1)+P(A2)*P(B/A2)=M/N * M-1/N-1 + N-M/N * M/N-1 = M/N
.
1, 2n ,
1 + 2+n=Ω, ()>0
:
P(Ak│B)=(P(Ak)P(B│Ak))/P(B)=(P(Ak)P(B│Ak))/( =1∑n P(Ak) P(B│Ak)), (k=1,n)
-:
:
P(B Ak) = P(B) P(Ak│B) = P(Ak) P(B│Ak).
P(Ak│B)= (P(Ak) P(B│Ak))/P(B).
:
P(B)= =1∑n P(Ak) P(B│Ak).
. k . . (k) , , P(Ak│) , , .
.
2 N . 1- M1 , 2 . : , ½ 1- 2- , ( ) n . ,
|
|
2 :
1) 1={ 1- }
2) 2={ 2- }
:
P(A1)=P(A2)= 1/2
, (│k) = (Mk/N)n/
:
(k│) = (1/2 (Mk/N)n)/(1/2 (M1/N)n + ½ (M2/N)n)=Mkn/(M1n+ M2n), k=1,2.
1<M2, n→¥ P(A2│B)=1/(1+(M1/M2)n)→1, .. 1/M2<1
. , , , .
. , () = () (). () ≠ () (), .
()=0, .
.
52 (13 ) . = , = . , .
.. ()= ()(), .
. 1, 2n , 1≤i1<i2<<im, 2≤m≤n
(Ai1,i2im)=P(Ai1) P(Ai2)P(Aim).
.
, 2 , . (), (), p, q, q=1-p. n .
Ω={ω=(x1,xn), xk=,, k=1,n}.
, (x1,xn)=(x1)(xn), (xk)=p, xk=, (xk)=q, xk=.
n , . 0,1,2,n , , , n k .
Sn .
. k = 0,1,n
P(Sn=k)=Cnkpkqn-k
-:
:
ω=(ͅͅͅͅ).
? , n k ( ), .. Cnk. pkqn-k, .. .
: , : k=0∑n Cnk pk qn-k =(p+q)n=1
: , , , ( ), .
.
. (Ω, , ) . X , Ω , F(x)=P{X<x}=P{ω│P(ω)<x}. F(x) X.
|
|
:
Ω , , Ω, .
:
1. x1<x2 P{x1≤X<x2}=F(x2)-F(x1)
2. F(x)#( ).
3. limx→-∞F(x)=0, limx→∞F(x)=1
4. F(x) (.. limx→x0 - 0F(x)=F(x0)).
1 . 2 1. 3 .
. X Y , P{X<x, Y<y}= P{X<x}P{Y<y} ( , {X<x} {Y<y} )
, , .
:
n .
Xi =1, i- , 0, .
Sn = X1+X2++Xn. Sn n .
. X
MX=∑xi P{X=xi}, xi X.
. () X DX=M(X-MX)2, X-MX . .
. Cov(X,Y)=M((X-MX)(M-MY)) X Y, .
. X Y. X Y ρ (X,Y)=(Cov(X, Y))/√D X D Y