ThmDex – An index of mathematical definitions, results, and conjectures.
I.I.D. real weak law of large numbers under finite second absolute moments
Formulation 0
Let $X_1, X_2, X_3, \ldots \in \text{Random}(\Omega \to \mathbb{R})$ each be a D3161: Random real number such that
(i) $X_1, X_2, X_3, \ldots$ is an D3358: I.I.D. random collection
(ii) \begin{equation} \exists \, \mu \in \mathbb{R} : \mathbb{E} X_1 = \mu \end{equation}
(iii) \begin{equation} \mathbb{E} |X_1|^2 < \infty \end{equation}
Then
(1) \begin{equation} \frac{1}{N} \sum_{n = 1}^N X_n \overset{L^2}{\longrightarrow} \mu \quad \text{ as } \quad N \to \infty \end{equation}
(2) \begin{equation} \frac{1}{N} \sum_{n = 1}^N X_n \overset{p}{\longrightarrow} \mu \quad \text{ as } \quad N \to \infty \end{equation}
Proofs
Proof 0
Let $X_1, X_2, X_3, \ldots \in \text{Random}(\Omega \to \mathbb{R})$ each be a D3161: Random real number such that
(i) $X_1, X_2, X_3, \ldots$ is an D3358: I.I.D. random collection
(ii) \begin{equation} \exists \, \mu \in \mathbb{R} : \mathbb{E} X_1 = \mu \end{equation}
(iii) \begin{equation} \mathbb{E} |X_1|^2 < \infty \end{equation}
This result is a particular case of R2343: Uncorrelated real weak law of large numbers. $\square$