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8 votes
1 answer
3k views

Expectation of the maximum of two correlated normal variables

I am curious what the derivation for the expectation of the maximum of two jointly normal random variables $X$ and $Y$ with correlation coefficient $\rho$. I could start with the following but the ...
7 votes
1 answer
411 views

Estimation of a uniform distribution corrupted by Gaussian noise

Problem definition I have a dataset composed by $m$ observations $y^{(1)},\dots,y^{(m)} \in \mathbb{R}^2$ generated as follow \begin{equation*}\begin{aligned} y &= z + v \newline z & \sim\...
3 votes
1 answer
1k views

What is the distribution of max-min for a Gaussian distribution

For a process N(t), where at any instance of t=T0, the distribution of N(T0) is Gaussain with mu=0: What is the distribution of max(N(t))-min(N(t))? From my simulation, it has some non-zero positive ...
5 votes
2 answers
272 views

Unbiased Estimator of Largest Mean of Two Normal Distributions

Given samples from two normal distributions: $X_i \stackrel{iid}{\sim} \mathcal{N}(\mu_X, \sigma_X^2)$ for $i = 1,...,n$ $Y_i \stackrel{iid}{\sim} \mathcal{N}(\mu_Y, \sigma_Y^2)$ for $i = 1,...,n$ How ...
0 votes
0 answers
25 views

Separating components of a likelihood maximization

Apologies for the naive question, but I have a problem I would like to solve. Suppose I have a two dimensional likelihood of the form $L \propto \exp\{-\frac{1}{2}\} \begin{bmatrix}x & y\end{...
1 vote
0 answers
51 views

Distribution of the difference between the maximum of $n$ identical and correlated Gaussian random variables and any one of them

Suppose, there are $n$ identical and correlated Gaussian random variables namely, $X_1, X_2, ..., X_n$ with $X_i\sim\mathcal{N}(0,\sigma^2)$ for all $i\in\{1,2, ...n\}$. The correlation coefficient ...
3 votes
2 answers
289 views

Does the following distribution converge to anything?

Consider the following process for generating a random sample: Sample $X_1, X_2, \dots, X_n \sim \mathcal{N}(0,1)$ Compute $M = \max\limits_i |X_i|$ Scale the values to get $Z_i = X_i / M$ Can we ...
15 votes
2 answers
21k views

What is the distribution for the maximum (minimum) of two independent normal random variables?

Specifically, suppose $X$ and $Y$ are normal random variables (independent but not necessarily identically distributed). Given any particular $a$, is there a nice formula for $P(\max(X,Y)\leq x)$ or ...
0 votes
0 answers
41 views

Identifiability of a bivariate normal distribution with identified minimum

I am suffering from to understand a proof of a paper. (Nádas, Arthur. "The distribution of the identified minimum of a normal pair determines' the distribution of the pair." Technometrics 13....
0 votes
0 answers
34 views

Find maximum of bimodal posterior pdf

can you help find the maximum (analytically) of the following posterior pdf? $p(\theta|x) = \frac{\alpha}{\sqrt{2\pi}}e^{-\frac{1}{2}(\theta-x)^2} + \frac{1-\alpha}{\sqrt{2\pi}}e^{-\frac{1}{2}(\theta+...
12 votes
2 answers
489 views

Expected value of spurious correlation

We draw $N$ samples, each of size $n$, independently from a Normal $(\mu,\sigma^2)$ distribution. From the $N$ samples we then choose the 2 samples which have the highest (absolute) Pearson ...
3 votes
1 answer
331 views

Extreme value distribution for multivariate normal

I have a series of data sets. Each data set represents a measurement in 3D space relative to a global origin. I want to model the extreme values of my data. If I were to calculate the extreme radius ...
24 votes
2 answers
11k views

Distribution of the maximum of two correlated normal variables

Say I have two standard normal random variables $X_1$ and $X_2$ that are jointly normal with correlation coefficient $r$. What is the distribution function of $\max(X_1, X_2)$?
9 votes
1 answer
2k views

Approximating the mathematical expectation of the argmax of a Gaussian random vector

Let $X = \left( {{X_1},...,{X_n}} \right) \sim \mathcal{N}\left( {{\mathbf{\mu }},{\mathbf{\Sigma }}} \right)$ be a Gaussian random vector and $I = \mathop {\arg \max }\limits_{i = 1,n} {X_i}$. $I$ ...
5 votes
2 answers
1k views

CDF of maximum of $n$ correlated normal random variables

The maximum of $n$ normal i.i.d. random variables $$Y=\max\{x_1,...,x_n\},$$ $$x_i \sim N[0,1]$$ has the CDF $$P(Y\le y)=\Phi(y)^n $$ but how does the CDF look like, if the variables are identically ...
1 vote
0 answers
36 views

Given 5 variables, all independently normally distributed, what is the probaility that variable A is lower than the other 4 variables?

Suppose variables A B C D and E are independent, normally distributed, with known variance and mean. What is the probability that A is less than B and C and D and E? Essentially, I have model ...
1 vote
0 answers
125 views

Distribution of maximum of sample means

Let $X_1, ..., X_n$ be a sample from $N(\mu, 1)$. Fix $1 \leq m<n$ and define $$T_i= \frac{1}{m}\sum\limits_{j=i}^{i+m-1} X_j,$$ for $i \in \lbrace 1, ..., n-m+1 \rbrace$. We have the test that ...
1 vote
1 answer
256 views

Expectation of Maximum and Minimum of Partial Sums of Normal Random Variables

Peggy Strait, 1974, Pacific Journal of Mathematics ON THE MAXIMUM AND MINIMUM OF PARTIAL SUMS OF RANDOM VARIABLES Gives a nice result (4.3) and (4.4) in terms of "standard normal random variables&...
32 votes
3 answers
17k views

Extreme Value Theory - Show: Normal to Gumbel

The Maximum of $X_1,\dots,X_n. \sim$ i.i.d. Standardnormals converges to the Standard Gumbel Distribution according to Extreme Value Theory. How can we show that? We have $$P(\max X_i \leq x) = P(...
1 vote
0 answers
232 views

Maximum absolute from complex Gaussian distribution

Consider a random variable $Y$ with complex Gaussian distribution, i.e $Y \sim \mathcal{C N}(\mu,\sigma^2)$. We can write $Y$ as real ($Y_r$) and imaginary component ($Y_j$) as $Y = Y_r + i Y_j$. ...
0 votes
1 answer
50 views

Optimal way to rank candidates - concrete statement

I'd like to have some statistical/probabilistic formalisations (solutions..) of the following concrete case I have heard : "Imagine you have a set of candidates to be interviewed for a job. You ...
2 votes
1 answer
693 views

The probability that the minimum of a multivariate Gaussian exceeds zero

Suppose $$X \sim \mathcal N_n(\text{diag}(\Sigma), \sigma^2 \Sigma)$$ where $\Sigma$ may be allowed to be low rank, and let $Y = \min_i > X_i$. What can be said about $P\left(Y \geq 0\right)$? In ...
3 votes
0 answers
194 views

Distribution of the minimum of the squared Euclidean norm of a $N(\mu,\Sigma)$ random variable

Suppose that $X^n := \{x_1, x_2, \ldots, x_n\}$ is a sample of $n$ i.i.d $p$-dimensional points, where $X \sim N(\mu, \Sigma)$. What is known about the distribution of $\min_{x_i \in X^n} \|x_i\|^2_2$?...
1 vote
0 answers
142 views

Expectation of a sequence of random variables based on a set of iid Gaussian random variables

This is a rather convoluted problem: I'll my best trying to explain it. So, we have $m$ iid standard Gaussian RVs $Q_i$. We get a realization from each of them, and these values $q_1,\dots,q_m$ are ...
1 vote
1 answer
456 views

Distribution of minimum distance in a iid Gaussian sample

$X_1,...,X_n$ denotes an iid sample with the same Gaussian distribution. I am interested in the distribution of the following quantity. We first pick $i \in [n]$ Then we extract $j^* \in argmin_{j\...
5 votes
1 answer
303 views

MLE for the maximum of n values that are observed only with noise

Suppose $x_1, ..., x_n$ is a fixed set of real numbers. Let $\epsilon_1, ..., \epsilon_n \sim N(0, \sigma^2)$ be i.i.d. with known $\sigma^2$, and suppose we get to observe only $z_i = x_i + \...
3 votes
1 answer
600 views

Limiting distribution of maximum of i.i.d. Gaussians with decreasing variance

Consider a random vector $X^{(m)} = (X^{(m)}_1,\dots,X^{(m)}_m)$ where, for fixed $m$, the elements of $X^{(m)}$ are i.i.d. $\mathcal{N}(0,\sigma^2 / m)$. Define $$Z_m =\max_{k=1,\dots,m}X^{(m)}_k.$$...
2 votes
0 answers
1k views

maximum gap between order statistics of normally distributed random variables [closed]

I am currently working on a not-that-easy problem involving order statistics. As I am unsure as to how I could solve it, I thought it might already possess a solution. So here I am, my questions is: ...
11 votes
2 answers
8k views

Decision trees, Gradient boosting and normality of predictors

I have a question regarding the normality of predictors. I have 100,000 observations in my data. The problem I am analysing is a classification problem so 5% of the data is assigned to class 1, 95,000 ...
2 votes
1 answer
395 views

Convergence maximum of Normal rv to gumbel through simulation (metropolis hastings)

I would like to see the convergence of an order statistic to its respective Extreme Value attractor by simulating with the Metropolis Hastings algorithm (I am self-studying MCMC algos). I was trying ...
2 votes
1 answer
580 views

Distribution with 3 Modes, Find the 2 In-Between Minima

Suppose I have a dataset consisting of numbers drawn from three normal distributions $\mathcal N\!(\mu_{\rm left}, \sigma_{\rm left}^2),\ \mathcal N\!(\mu_{\rm center}, \sigma_{\rm center}^2),\ \...
7 votes
2 answers
286 views

What is the distribution of a bivariate normal component conditional on the max of the other component?

Let $n$ be a large integer, and consider two independent multivariate Gaussian $n$-vectors $x, z$ with $x\sim\mathcal{N}\left(0,I\right),$ and $z\sim\mathcal{N}\left(0,\sigma^2 I\right)$. Let $y=x+z$. ...
3 votes
1 answer
683 views

Variance of the maximum of linear combinations of iid normal random variables

Let $X_i$ for $i\in\{1,\dots,n\}$ be a set iid normally distributed random variables with mean $\mu$ and variance $\sigma^2$. Let $Y_j$ for $j\in\{1,\dots,2^n\}$ be a positive linear combination of ...
0 votes
0 answers
51 views

Estimate true mean of the maximum of N sample means

Let's say we have N distributions $\mathcal N(\mu_i, \sigma_i)$, each with unknown mean $\mu_i$ and unknown standard deviation $\sigma_i$, $i=0,...,N-1$. For each $i$, $M$ independent random samples ...
3 votes
1 answer
5k views

Expectation of max of two normal random variables

I have been reading this paper about the maximum and minimum of two normal distributed variables. Inside the paper there is the formula for the expectation of this the maximum of the two variables. ...
0 votes
1 answer
159 views

Interpretation of a Gumbel distribution's results

I am using (essentially) the approach outlined in the paper "Statistical-based WCET estimation and validation" (http://drops.dagstuhl.de/opus/volltexte/2009/2291/pdf/Hansen.2291.pdf) to build a Gumbel ...
9 votes
1 answer
9k views

Expected value of minimum order statistic from a normal sample

UPDATE Jan 25th 2014: the mistake is now corrected. Please ignore the calculated values of the Expected Value in the image uploaded - they are wrong- I don't delete the image because it has generated ...
4 votes
1 answer
87 views

Integral from the Adversarial Spheres paper (maximum of the difference between a constant and a normal random variable)

I'm trying to follow a proof in the Adversarial Spheres preprint on arXiv. The proof requires the computation of the integral in Appendix F, page 14: $$\mathbf{E}\left[\max\left(\sqrt{2}\left(\frac{\...
1 vote
1 answer
351 views

Approximation/bound to a_n and b_n in normal maxima to Gumbel

I was reading this which tries to find $a_n$ and $b_n$ such that $$F\left(a_n x+b_n\right)^n\rightarrow^{n\rightarrow\infty} G(x) = e^{-\exp(-x)},$$ where $F$ is the cdf of a standard normal. The ...
4 votes
0 answers
189 views

Extreme value distribution for univariate normal: Derive parameters of the Gumbel [duplicate]

I have a question regarding the extreme value distribution corresponding to i.i.d. samples $X_i$ from a normal distribution, say $X_i\sim N(\mu, \sigma^2)$. According to the theorem of Fisher-Tippett-...
13 votes
3 answers
1k views

Does there exist someone faster than Usain Bolt today?

EDIT: I am more interested in the technical issues and methodology of determining the likelihood of a "true" maximum in a given population given a sample statistic. There are problems with estimating ...
0 votes
0 answers
54 views

Drawing the smallest value from a set of distributions

I have a specific number of normal distributions $N_D$ all with their own mean $\mu$ and std $\sigma$. Now I obtain a sample from all distributions which results in a set of $N_D$ samples. What is the ...
5 votes
1 answer
112 views

Distribution of $\dfrac{X_{i}}{\max X_{i}}$?

Suppose we have a sample of standard normal i.i.d. observations $X_{1}, X_{2}, \cdots ,X_{n}$, what can we say about the asymptotic distribution of $V_{i}$ and $W_{i}$, where: $V_{i}=\dfrac{X_{i}}{\...
1 vote
0 answers
46 views

Probability that the Maximum of Many Normal Draws from Multiple Classes is of one Class

Given a set of $N=n_i+n_j+n_k$ draws from distributions $N(\mu_i,\sigma_i^2), N(\mu_j,\sigma_j^2), N(\mu_k,\sigma_k^2)$, what is the probability that the maximum drawn value was from distribution $i,j,...
1 vote
0 answers
308 views

Could the sum of two normally distributed random variables be a GEV distribution?

I'm playing with Matlab, I have got a test statistic $T$ wich is of the form : $$T(x)=\sum_{i=1}^{n}f_{i}(x)+\sum_{i=1}^{n}g_{i}(x)+c $$ Where $f$ and $g$ are functions of the observations $x$, $n$ is ...
1 vote
0 answers
53 views

Mean & Variance after applying a Maximum function n-times [closed]

I am trying to solve a statistics problem with very little statistics theory. I can determine a solution to my problem by writing a simulation program, but I really need to have the proper formula ...
0 votes
1 answer
191 views

How to find the maximum likelihood of this scenario occurring?

I have the equation: $ 0= 2.01106 - 0.00274(34.647+24.24a)-0.02059(45.647+21.122b)+1.37984(2.05-0.206c)-0.01176(10.588+11.963d)+0.00394(118.29-21.097e)-0.03552(92.17+2.855f)$ I have the above ...
4 votes
1 answer
442 views

Using extreme value theory to estimate bounds

Suppose I have I have a random variable $X$ that I know is doubly bounded on support $[0,\theta]$ but I dont know $\theta$ (we don't know anything on the distribution of $X$, but assume it is not ...
3 votes
0 answers
770 views

GEV of Normal Distribution and relationship of the parameters

My question goes on Extreme Value Theory for the Normal distribution (www.math.ethz.ch/~embrecht/RM/chap7.pdf): Which type of GEV (Generalized Extreme Value) distribution does the Normal distribution ...
5 votes
1 answer
169 views

Distribution of Extreme Spread for n, sigma

Simple form provided by WHuber: What is the distribution of the diameter of n points in the plane drawn iid from a bivariate Normal distribution? (Diameter is the greatest distance among any pair of ...