Chapters
II
: Proofs of the
laws
- f large Number
II of large Number Lattin in probability almost convergence - - PowerPoint PPT Presentation
Chapters : Proofs of the laws II of large Number Lattin in probability almost convergence convergence sure - - " weak " strong " " cow corn Two tests for stray convergence - O almost sure conveyance . ) - X
Chapters
: Proofs of the
laws
Lattin
almost
sure
convergence ⇒
convergence
in probability
corn
" " weakcow
"
Two tests for stray
convergence
① Fe > 0
All Xu
② VE>O E P( IXn
⇒ almost sure convergence
① Prove
S LLN
Then I WLLN)
If
X , ,Xn,
. -is
a sequence of independent randomvariables and
there
exist
m , VER so
That IECXi)
and
W ( Xi) EV
fer
all
i
, then theRuden variables
Sn
m
in probability
:V-E > 0
,
"I
IP ( Isn
PI (Proof
relies
Observe
:
IECSN)
Non)
t-etxnll-ntwlxit.tk)
need'T ta ( NIX ,)t
. - -TNCXNDEIindef
n
Chebyshev
says
:IP ( Isn
a- *l s
E
Take
"I
canboth
sides
.Ed
.Then ( SUN)
If
X , ,Xn,
. -is
a sequence of independent randomvariables and
there
exist
m , a EIR so
That IECXI)
and
⇐(Ni
") Ea
fer
all
i
, then theRuden variables
Sh
m
almost surely
:PC
"ash
Pt
WLOG
we assume
m
Its
'a
fact
that
for all
ZEIR
we
have
z2sz4tl
.Hence
LEI Xi ' )
= N (Xi) EIE ( Xi't 1) E
att
.Strategy
: let
Ta
, and
we'll study
⇐ ( Tn
")
.We'll
show
⇐( Tn' ) isn't
"too
big
" ,
from
which
we'll
be
able to use
Markov
to
prove
The
result
.IE ( Tn 4)
= IE( Nit"
t ¥ ,.bg?,i2Wt..?..KfixiXk
Vakil
+ §
;
4 Xi' Xi
t
e
24 Xi Xi Xk Xe)
IE (Xi
") t
6
ECxi.IE Hilt 12 ?g
,.IE#7leYxi%Efxd
+ 4.7, let xi7Ex 24 EE
Exile
⇐ ( Tn
")
IECXI
") t 6¥ ECxi.IE (Xi)
← ?
a
t
6 ÷
,
Cath Catt )
=na
t
6 (2) (att) '
=nut Kalla
← n' a
t
3 n
s
na k
← K
'
⇐( Tn 4) En
So
: IEC Tn 4) E n
Markov
says
:lP(l9nl)=lP(HHt-tXal)=lPlIlTnl)hh
IP ( I SnIs E)
= IP (
'a Itn Is E)
( Tn
" s
n
" E")
e ⇐n!I
E nn¥g
,
= Kant.
So
: qH ( Isak E) E E E
. In. c is
.By The
Borel
version
the test
fer
almost
sure
conveyance
,
we
get
Sn converge
to
almost
DUE
surely
. .Bh