WLLN

deejayosamu·2025년 7월 14일

통계 기본 개념

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확률수렴(Convergence in probability)

Def)
XnpXX_n \overset{p}{\rightarrow} X <=> ϵ>0,limnP(XnXϵ)=0\forall \epsilon >0, \displaystyle \lim_{n \to \infty} P(|X_n-X| \geq \epsilon) = 0

WLLN(Weak Law of Large Number)

For iid random sample X1,...,XnX_1,...,X_n
Xnpμ\overline{X_n} \overset{p}{\rightarrow} \mu if μ=E(X1)\mu =E(X_1) & Var(X1)<Var(X_1) < \infty
pf)

Continuous Mapping Theorem

If XnpXX_n \overset{p}{\rightarrow} X & YnpYY_n \overset{p}{\rightarrow} Y, then g(Xn,Yn)pg(X,Y)g(X_n,Y_n) \overset{p}{\rightarrow} g(X,Y) for any continuous function gg.

ex1)
If XnpμX,YnpμY\overline{X_n} \overset{p}{\rightarrow} \mu_X, \overline{Y_n} \overset{p}{\rightarrow} \mu_Y, then
3(logXn)Ynp3(log μX)μY3(log \overline{X_n})^{\overline{Y_n}} \overset{p}{\rightarrow} 3(log \space \mu_X)^{\mu_Y}

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