n (), .
n :
np-q≤ ≥np+p
39. : . .
..- , .
.
.
X .
xi | x 1 | x 2 | x 3 | ... | xn | > xn |
pi | p 1 | p 2 | p 3 | ... | pn | |
F (xi) | p 1 | p 1+ p 2 | p 1+..+ pn -1 |
F (xi)=P{ X < xi }=P{(X = x 1)È(X = x 2)È... È(X = xi- 1)}= p 1+...+ pi -1.
, , .
, , , .
(5.5)
.
.
, ( , ) .
X , , x:
F (x)=P{ X < x }.
, X X (. 5.1). .
1. F (-¥) = 0. (5.2)
2. F (+¥) = 1. (5.3)
3. F (x) , .. x 1 < x 2
F (x 1) £ F (x 2).
. 5.2.
C ={ X < x2 } =A+B, A ={ X < x1 } B ={ x1£X<x2 }.
P (C)= P (A)+ P (B),
.. P { X < x2 }= P { X < x1 }+ P{x1£X<x2 },
F(x2)=F(x1)+P{ x1£X<x2 }.
P{ x1£X<x2 }£0, , F (x 1) £ F (x 2)
4. P(α£ X < β) = F (β) - F (α), "[α,β[ÎR. (5.4)
.
, α β ( α) .
, F(x) , 0 1: 0≤F(x)≤1, F(-∞)=0, F(+∞)=1.
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