. .
H1, H2, , Hn , :
P(A)= PH1(A)P(H1)+ PH2(A)P(H2)++ PHn(A)P(Hn) . H1, H2, , Hn .
: : AH1, AH2, , AHn. ( H1 ..) , = AH1+ AH2++ AHn. H1, H2, , Hn , AH1, AH2, , AHn. , : P()= P(AH1)+ P(AH2)++ P(AHn). P(AHi) PHi(A)P(Hi), .
:
, . , , 0,8, 0,9. , .
() = 0,5*0,8 + 0,5*0,9 = 0,85.
. .
:
.
, , .
: H1, H2, , Hn, . , , .
:
P(A)= PH1(A)P(H1)+ PH2(A)P(H2)++ PHn(A)P(Hn) (1)
, , . , , , , . ,
PA(H1), PA(H2), , PA(Hn).
:
(Hi) = () A(Hi) = (Hi)Hi ()
A(Hi) =
() (1),
:
. n=12 , m=4 n-m=8 , n=12 . . , .
.
4) k n .
, n , 2 { A; }. .. n , P(A)=q P()=q-1=p.
. . , k , n- k .
|
|
, . , n k ; B.
. , , . ,
. , , , . . n k, . , .
5) , p A .
n p e>0 , k n . |k-np|£en, .. -en £ k-np £ en np-en £ k £ np+en. , k1 £ k £ k2, k1 = np-en, k2 = np+en. , : P( . P( 2 .
: .. n=1, n .
6) X , m. , P (X ≥ 4) ≤ m/ 4.
m= (.. 1- , , ) ³ ( a 4, ) ³ = =4× P (X ³4). P (X ≥ 4) ≤ m/ 4.
( 4 ).
7) , X Y , , M(XY)=M(X)M(Y)
x1 | x2 | |
p1 | p2 |
M(XY) = x1p1+ x2p2 +
X Y , ( ).
: X x1, x2, , Y - y1, y2, pij=P(X=xi, Y=yj). XY . M(XY)= X Y : P(X= xi, Y=yj)= P(X=xi) P(Y=yj). P(X=xi)=ri, P(Y=yj)=sj, pij=risj
, M(XY) = = . , : M(XY)=()() = M(X)M(Y), .
8) , X Y , , M (X + Y) = M (X) + M (Y).
x1 | x2 | |
p1 | p2 |
M(XY) = x1p1+ x2p2 +
: M(X+Y)= M(X)+M(Y).
: X x1, x2, , Y - y1, y2, pij=P(X=xi, Y=yj). X+Y . M(X+Y)= . : M(X+Y)= . . , - (X=xi, Y=y1), (X=xi, Y=y2), , P(X=xi). . , . : M(X+Y)= M(X)+M(Y), .
|
|
9) , n . , ()=n, D()=n(1-).
n , , Ā q=1-p. . n . : =1+2++n. , (i)=, D(i)=np. . , :
q |
, ()=, 2 , D()=(2)-2()=-2=(1-)=q. , (i)=, D(i)=pq. ()=(1)+..+(n)=n. i , : D()=D(1)++D(n)=npq=np(1-).
10) X , λ. , M (X) = λ.
:
X | |||||
P | e-λ | λ e-λ |
:
=
, λ, , X.
11) , . , M (X) = .
1- . , q = 1-p. :
n | |||||
pq | pqn-1 |
, ,
.
, .
12) , .
: : . .
: Z = . . , . , , |ρ|≤1.
13) f (x)? , X D (X) , M (X) .
X f(x) m = M(X) ,
.
X [a, b],
∞ - , , .
14) , () = μ.
...
, μ .
..,
. . , ,
|
|
. μ ( ).
, M(X)=μ, .. μ.
15) , D(X) = σ2.
...
, - . z=(μ)/ . . , , , u=z, , ., .
16) , , , .
, X, , , λ>0 :
M(X)=
, u = x, dv = e λ x d (λ x), du = dx, v = e λ x .
, M(X)= .
17) C . , ,
k (k N) . k- .
k . k- :
: ,
-:
- .
18) - , - .
, :
:
19) [,b].
A=μ3/σ3 ,
Ex= μ4/σ4-3 .
.
20) (X, Y), a ≤ x ≤ b, c ≤ y ≤ d.
:
, .
.
, .