. 2.1 . , , , .
(¥, ), . , X x 1, xi (¥, x) .. , <. , , X , , , , . = {<} :
(X < x) = F (x). (2.5.1)
. X ( < ) , , X , .
P (X < x) = F (x) X .
F (x).
1. F (x) [0, 1], . e. 0 ≤ F (x) ≤ 1, F (x) .
2, F(x) , . . F (x 1)≤ F (x 2) 1 < 2.
, F (x).
3. P (x 1 ≤ X < x 2) = F (x 2) F (x 1) (2.5.2)
. , < 2, :
( < 2) = (x 1≤ X < x 2) + (X < x 1),
P ( < 2) = P (x 1≤ X < x 2) + P (X < x 1),
P (x 1≤ X < x 2) = P ( < 2) P (X < x 1) = F (x 2) F (x 1).
4 F (¥) = 0 F (+¥) = 1.
4 (2.5.1). F (x) . . 1.
:
. 2.6.
(, + Δ ). (2.5.2)
P (x < X < x + Δ x) = F (x + Δ x) F (x)
. 2
. [ x, x +Δ x ]
. Δ x →0 f (x),
, y = f (x), , . 2.
f (x).
1. f (x) ≥ 0 .
2.
(2.6.1)
. (. 3)
3.
(2.6.2)
. (. 121)
(2.6.3)
4.
(2.6.4)
.
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5. , . .
(2.6.5)