3
votes
2answers
52 views

Let $\{X_n\}$ be i.i.d integrable r.v.s, show that $\frac{1}{n}\max_{1\leq j\leq n}|X_j|\to 0 \quad \mbox{a.e.}$

This problem is an exercise in Probability theory,independence,interchangeable, martingale(Chow), exercise 4.1.10. Let $\{X_n,n\geq 1\}$ be independent identical distributed integrable random ...
3
votes
0answers
39 views

How to show $nP\{|X|>n\}\to 0$ as $n\to\infty$, but $X$ is not integrable.

How can I construct a random variable $X$ such that: $nP\{|X|>n\}\to 0$ as $n\to\infty$, but $X$ is not integrable.
0
votes
1answer
24 views

Length of life of a fire detector

The length of life of a flame detector is exponentially distributed with paramater $\lambda=0.1/year$. Die number of events which activate the flame detector in an interval with length $t$ (heat, ...
0
votes
2answers
32 views

How to determine the conditional expectation $\mathbb{E}[x^2\mid y]$

If $[x,y]^{T}$ is a two dimensional Gaussian random variable with zero mean and \begin{equation} \mathbb{E}[x,y]^{T}[x,y]=\begin{bmatrix} \sigma_x^2 & r_{xy}\\ r_{yx}& \sigma_y^2\\ ...