, .
, .
, .
, .
.
. :
( + ) = () + ()
.
. , n, , p . c , . , + + p .
() = /, () = p/, ( + ) = ( + p)/,
.
.
:
(+ +) = () + () +()
:
(+ +) = () + () +() ()
:
(+) = () + () ()
1, 2,..., n , :
(1) + (2) +.+(n) =1
, . :
() + (Ā) =1
, , . (|).
, .
(|) = (), (|) = ().
1. 10 : 3 , 5 2 . , ?
() = 3/10, ()= 5/10.
,
( + ) = () + () = 3/10 + 5/10 = 8/10
|
|
2. : () = 0,7 ()=0,8. ( ) .
, .
( + ) = () + () - () = 0,7 + 0,8 - 0,7 0,8 = 1,5 - 0,56 = 0,94.
.
1. , , . .
1. 2 2 . . , P(A) = 1/2. , . P(B) = 1/2, . . .
, . , , . . , , , .
, , , .
2. . (B|A) , , . , (B|A) = 1/3.
(|) = ().
(|) ǂ ().
1. , , :
P(AB) = ()(B|A)= P(B)P(A|B)
.
n p , , , .
(1) () = p/ = /n p/= ()(|A),
.
. (1) ,
() = ()(A|B).
= ,
(2) (AB) = P(B)P(A|B)
(1) (2),
()(|A) = ()(|B)
2. 2 2 . . . , . : ? (1) :
() = ()(|A) =1/2 1/3 = 1/6.
3. 70% , 21% . . . , ?
, , . () = 0,3, () = 0,21.
(1)
P(AB) = ()(B|A)
P(MK) = (M)(K|M)
,
|
|
P(K|M) = (MK) / (M)
P(K|M) = 0.21/ 0.3 = 0.7
4. 20% , 12% . . , ? , ?
.
, , Ɨ , ̗ . () = 0.2, (A) = 0.12, (A) = 0,08.
,
P(|A) = (A) / () = 0.12/ 0.2 = 0.6
P(M|A) = (AM) / () = 0.08/ 0.2 = 0.4
5 ( ). 1000 . 600 400 . 240
. 120 . ?
.
, . , ,
P(B)= (240 +120)/ 1000 = 0.36;
P(B|A)= (400)/ 1000 = 0.40;
0.36 ǂ 0.4, .
2.
(3) () = ()()
, , (|A) = () (1) (3)
, . .
(1 2... n) = (1)... (n).
6. , ( ) 0,8, ( ) 0,7.
, () = 0,7 0,8 = 0,56.