❙❯❻ ❚❍➮◆● ❑➊
!♥ ❤➜% &
◆➤♥❣✱ ✷✵✶✾
!♥ ❤➜% & ✶✴✼✼
❤"#♥❣ ✷✳ ❇✐➳♥ ♥❣➝✉ ♥❤✐➯♥
✶✳ ,♥❤ ♥❣❤➽❛
❍➔♠
X
①→❝ ✤(♥❤ +,➯♥ ❦❤/♥❣ ❣✐❛♥ ♠➝✉
✈➔ ♥❤➟♥ ❣✐→ +,( +,♦♥❣
R
✤89 ❣:✐ ❧➔ ❜✐➳♥ ♥❣➝✉
♥❤✐➯♥ ♥➳✉ ✈>✐ ♠:✐
xR
+➟♣ ❤9♣ ❝→❝ ➳+ A✉↔
{ω:X(ω)< x}
❧➟♣ +❤➔♥❤ ♠C+ ❜✐➳♥ ❝D
♥❣➝✉ ♥❤✐➯♥✳
➟♣ ❤9♣ ❝→❝ ❣✐→ +,( ❝G❛
X
✤89 ❣:✐ ♠✐➲♥ ❣✐→ +,( ❝G❛
X
❦➼ ➺✉
X(Ω)
◆L✐ ♠C+ ❝→❝❤ +,M❝ A✉❛♥✱ ❜✐➳♥ ♥❣➝✉ ♥❤✐➯♥ ❧➔ ♠C+ ✤↕✐ ❧89♥❣ ❝L +❤➸ ♥❤➟♥ ❣✐→ +,( ♥➔ ❤❛
❣✐→ +,( ❦❤→❝ ♣❤Q +❤✉C ✈➔♦ ➳+ A✉↔ ❝G❛ ♣❤➨♣ +❤S✳
❱➼ ❞3
●✐❡♦ ♥❣➝✉ ♥❤✐➯♥ ❧➛♥ ♠/0 ✤2♥❣ ①✉✳ ●5✐
X
❧➔ 78 ❧➛♥ ♠➦0 7➜♣ ①✉➜0 ❤✐➺♥✳ ❑❤✐ ✤>
X
❧➔
♠/0 ❜✐➳♥ ♥❣➝✉ ♥❤✐➯♥ ♥❤➟♥ ❝→❝ ❣✐→ 0DE ✵✱ ✶✱ ✈➔ ✸✳
●5✐
Y
❧➔ 78 ♥❣KL✐ ✤➳♥ ✤M ①➠♥❣ O ❝P❛ ❤➔♥❣ ❆❇ 0D♦♥❣ ♠/0 ❑❤✐ ✤>
Y
❧➔ ❜✐➳♥ ♥❣➝✉
♥❤✐➯♥ ♥❤➟♥ ❝→❝ ❣✐→ 0DE ✵✱ ✶✱ ✷✱✳
●5✐
Z
❧➔ ❝❤✐➲✉ ❝❛♦ ❝V❛ ♠/0 ❤5 7✐♥❤ ♣❤M 0❤W♥❣ ✭✤Y♥ ✈E✿ ❝♠✮✳ ❑❤✐ ✤>
Z
❧➔ ❜✐➳♥ ♥❣➝✉
♥❤✐➯♥ ♥❤➟♥ ❝→❝ ❣✐→ 0DE 0D♦♥❣ ❦❤♦↔♥❣
(0,+)
!♥ ❤➜% & ✷✴✼✼
4❤➙♥ ❧♦↕✐
❇◆◆ ,U ,↕❝✿ ❇◆◆ ❝L +➟♣ ❣✐→ +,( ❝L WD ❧89♥❣ ❤X✉ ❤↕♥ ❤♦➦❝ ✈/ ❤↕♥ ✤➳ ✤89❝✳
❇◆◆ ❧✐➯♥ +Q❝✿ ❇◆◆ +❤Z❛ ✤✐➲✉ ❦✐➺♥ W❛✉✿
+➟♣ ✐→ +,( +↕♦ +❤➔♥❤ ✤♦↕♥✱ ❦❤♦↔♥❣ ❤♦➦❝ ❤9♣ ❝→❝ ✤♦↕♥✱ ❦❤♦↔♥❣✳
>✐ ♠:✐ +❛ ❝L
P(X=c) = 0
❈❤➥♥❣ ❤↕♥ ` ❱➼ ❞Q ✶✱
X, Y
❧➔ ❝→❝ ❇◆◆ ,U✐ ,↕❝✱ ❝b♥
Z
❧➔ ❇◆◆ ✐➯♥ +Q❝✳
✷✳ ❍➔♠ ♣❤➙♥ ♣❤=✐
,♥❤ ♥❣❤➽❛✿
❍➔♠ WD +❤M❝
FX(x) = P(X < x), x R
✤89 ❣:✐ ❧➔ ❤➔♠ ♣❤➙♥ ♣❤D✐ ❝G❛
❜✐➳♥ ♥❣➝✉ ♥❤➯♥
X
◆❤➟♥ ①➨B✿
❍➔♠ ♣❤➙♥ ♣❤D✐
FX(x)
❝❤➼♥❤ ❧➔ ①→❝ W✉➜+
X
♥❤➟♥ ❣✐→ +,( +,♦♥❣ ❦❤♦↔♥❣
(−∞, x)
!♥ ❤➜% & ✸✴✼✼
➼♥❤ ❝❤➜&
0FX(x)1,xR
FX(x)
✤#♥ ✤✐➺✉ ❤)♥❣ ❣✐↔♠ ✈.✐ ♠/
xR
FX(x)
❧✐➯♥ 23❝ 25→✐ ✈.✐ ♠/✐
x
28❝ ❧➔
lim
xx
0
FX(x) = FX(x0),x0R
✈✮
lim
x+FX(x) = 1,lim
x→−∞ FX(x) = 0
◆❤➟♥ ①➨&✿
P(Xa) = 1 F(a)
P(aX < b) = F(b)F(a)
!♥ ❤➜% & ✹✴✼✼
❱➼ ❞.
❤♦ ❜✐➳♥ ♥❣➝✉ ♥❤✐➯♥
X
❝, ❤➔♠ ♣❤➙♥ ♣❤1✐
F(x) = a+b. arctan x, x R
❛✮ ❚➻♠
a
✈➔
b
❜✮ ❚➻♠
x
8❛♦ ❝❤♦✿
P(X1x) = 1/4
●✐↔✐✳
❛✳ ❝=✿
lim
x+F(x) = 1
lim
x→−∞ F(x) = 0 (a+
2= 1
a
2= 0 (a= 1/2
b= 1
❜✳
P(X1x) = 1 P(X < 1x) = 1 F(1 x)
= 1 1/2 + 1 arctan(1 x)= 1/21 arctan(1 x) = 1/4
❚@ ✤=✿
arctan(1 x) = π/4
❤❛
x= 0
!♥ ❤➜% & ✺✴✼✼
❱➼ ❞.
❤♦ ❜✐➳♥ ♥❣➝✉ ♥❤✐➯♥
X
❝, ❤➔♠ ♣❤➙♥ ♣❤1✐
F(x) =
0, x < 0
ax2+b, 0x < 2
1, x 2
❛✮ ❚➻♠
a
✈➔
b
❜✮ ❚➻♠ ❤➔♠ ♣❤➙♥ ♣❤1✐ ❝:❛
Y= 2X+ 1
●✐↔✐✳
❛✳ ❱➻
F(x)
❧✐➯♥ 23❝ 25→✐ ♥➯♥
lim
x0
F(x) = F(0)
lim
x2
F(x) = F(2) (0 = b
4a+b= 1 (a= 1/4
b= 0
!♥ ❤➜% & ✻✴✼✼
❚❤❡♦ ✤'♥❤ ♥❣❤➽❛✿
FY(y) = P(Y < y) = P(2X+ 1 < y)
=P(X < (y1)/2) = F((y1)/2)
=
0,(y1)/2<0
1/4[(y1)/2]2,0(y1)/2<2
1,(y1)/22
=
0, y < 1
1/16 (y1)2,1y < 5
1, y 5
!♥ ❤➜% & ✼✴✼✼
❇✐➳♥ ♥❣➝✉ ♥❤✐➯♥ +,✐ +↕❝
❈❤♦
X
❧➔ ✐➳♥ ♥❣➝✉ ♥❤✐➯♥ 56✐ 5↕❝ ✈:✐ ;➟♣ ❣✐→ ;5'
X(Ω)
❑❤✐ ✤@✱ ❤➔♠
p(x) = (P(X=x), x X(Ω),
0, x /X(Ω),
✤CD ❣E✐ ❤➔♠ ❦❤G✐ ①→❝ I✉➜; ✭♣5♦❜❛❜✐❧✐; ♠❛II ❢✉♥❝;✐♦♥✮✳
5♦♥❣ ;5C6♥❣ ❤D♣
X(Ω) = {x1, ..., xn}
❤O✉ ❤↕♥ ✈➔
pi=P(X=xi)
;❛ ❝@ ↔♥❣ ♣❤➙
♣❤G✐ ①→❝ I✉➜;✿
Xx1x2
✳✳✳
xn
P p1p2
✳✳✳
pn
◆❤➟♥ ①➨3✿
✐✮
Ppi= 1
✐✐✮ ❍➔♠ ♣❤➙♥ ♣❤G✐ ❝S❛
X
I➩ ❧➔
FX(x) = P(X < x) = X
xi<x
P(X=xi)
!♥ ❤➜% & ✽✴✼✼
❱➼ ❞8
!" ❧$ %↔♥ ♣❤➞♠ ❝- ✶✷ %↔♥ ♣❤➞♠✱ "1♦♥❣ ✤- ❝- ❝❤➼♥❤ ♣❤➞♠ ✈➔ ♣❤➳ ♣❤➞♠✳ ▲➜ ♥❣➝
♥❤✐➯♥ %↔♥ ♣❤➞ ●D✐
X
❧➔ %E ❝❤➼♥❤ ♣❤➞♠ "1♦♥❣ %↔♥ ♣❤➞♠ ❧➜ 1❛✳ ❚➻♠ ♣❤➙ ♣❤E✐ ❝J❛
X
①→❝ ✤M♥❤ ❤➔♠ ♣❤➙♥ ♣❤E✐ ✈➔ "➼♥❤ ①→❝ %✉➜"
P(1 X < 3)
●✐↔✐✳
❝@
X
❧➔ ✐➳♥ ♥❣➝ ♥❤✐➯♥ 56✐ 5↕❝ ♥❤➟♥ ❝→❝ ❣✐→ ;5'✿ ✵✱ ✶✱ ✷✳
P(X= 0) = C2
4/C2
12 = 1/11
P(X= 1) = C1
8C1
4/C2
12 = 16/33
P(X= 2) = C2
8/C2
12 = 14/33
❇↔♥❣ ♣❤➙♥ ♣❤G✐ ①→❝ I✉➜;✿
X
P
✶✴✶✶ ✶✻✴✸✸ ✶✹✴✸✸
!♥ ❤➜% & ✾✴✼✼
X
P
FX(x) = P(X < x) = X
xi<x
P(X=xi)
=
0, x 0
1/11,0< x 1
1/11 + 16/33,1< x 2
1/11 + 16/33 + 14/33, x > 2
=
0, x 0
1/11,0< x 1
17/33,1< x 2
1, x > 2
P(1 X < 3) = P(X= 1) + P(X= 2) = 16/33 + 14/33 = 10/11
X
X
X
Aii i = 1,2,3,4Ai
P(X= 1) = P(A1) = 0,7P(X= 2) = P(¯
A1A2) = 0,30,7 = 0,21
P(X= 3) = P(¯
A1¯
A2A3) = 0,30,30,7 = 0,063
P(X= 4) = P(¯
A1¯
A2¯
A3) = 0,30,30,3 = 0,027
X
PFX(x) = P
xi<x
P(X=xi) =
0, x 1
0,7,1< x 2
0,91,2< x 3
0,973,3< x 4
1, x > 4
X
X
H1, H2{H1, H2}
X
P(X= 0) = P(H1)P(X= 0|H1) + P(H2)P(X= 0|H2)
= 2/10 6/10 + 8/10 7/10 = 0,68
P(X= 1) = P(H1)P(X= 1|H1) + P(H2)P(X= 1|H2)
= 2/10 4/10 + 8/10 3/10 = 0,32
X
P
X FX(x)f(x)
FX(x) =
x
Z
−∞
f(t)dt, x R
f(x)X
f(x)0
+
R
−∞
f(x)dx = 1 f(x) = F
X(x)
f(x)
P(X=c) = 0 c
P(aXb) = . . . =P(a < X < b) = FX(b)FX(a) =
b
R
a
f(x)dx
f(x)FX(x) = Rx
−∞ f(t)dt