Page 149 - Math Grade 12 (Advance)

PROEUS DARA
3.

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3.1. snnmru
n. mnlilfliMti~

2
t3£mg'lJtrulhttHHtyncit~~1nf1Snt~13~1§t~~h !l Sbfl~Jcit~~h cr
2 2
cr2 = I.f(X- !l) H513S&Sgffit:HuH!U~ctl cr2 = I.fX - !12 '1
I.f u n I.f
3. mnt9~tHJ

§mgsm : h~Jci&s~Hd~tG~SJf:tlri x mbtf:tlru var(X) fiM~tf:tlru

Var(X) = E(X -11/ t~rn !l = E(X) '1 cr = Jvar(X) turlffi~ruln!Ucif:tl '1
!i'l
2 2 2
Var(X) = E(X- !l) = E(X - 2!lX + !l )
2 2 2 2 2 2 2
= E(X )- 2!lE(X) + E(!l ) = E(X )- 2!1 + 11 = E(X )- 11
2
2
Var(X) = E(X )- 11 2 fu.tlru !l = E(X) tS'"U !1 = E\X)
I
.
2
2
Var(X) = E(X ) - E (X) '1
tJf \;) I 0 tl tJ
tJ97UUM : HtGHtH:lSJtilti X HlS'iHn.flhttinTI50lli ~t;ghmn~:n~tun13 '1
U I
X 2 3 4 5
P(X = x) 0.1 0.3 0.2 0.3 0.1

~ 2
n. Var(X) ttilrutTI5ali13~ Var(X) = E(X- !l)

2 2
2. Var(X) ttilrut1Um13S Var(X) = E(X )-E (X) '1
Li u n
culm :
N

tJ:lUIS !l = E(K) = I.x x P(X = x)

= 1(0.1)+2(0.3)+3(0.2)+4(0.3)+5(0.1) = 3

2 2
tr:iOlS Var(X) = E(X- 3) = I.(x- 3) x P(X = x)

= 4(0.1)+1(0.3)+0(0.2)+1(0.3)+4(0.1) = 1.4

[:Jmsg Var(X) = 1.4 '1
u

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