Random Definition and 1000 Threads

Hi All Im hoping I am in the right area to ask this?!? Im looking for someones help. Is there a standard methodology or known equation for generating a random alpha numeric serial or incremental, which does not allow two characters to be used in sequence to each other which are near each other...

Given a continuous random vector (X,Y) with a joint density function In order to check whether it is indeed a joint density ƒ(x,y) the method is to check if ∫∫ƒ(x,y)dxdy=1 where the integrals limits follow the bounds of x and y. However, is it the case that if given an arbitrary discrete random...

Hello. I recall that the probability of generating a particular real number (in a bounded or unbounded interval) is exactly zero. If I keep generating reals for a limited amount of time, can I get a number more than once? About the computer, I know that the amount of different values the type...

So which method works better for random number generation(in terms of flatter frequency spectrum): transistor breakdown or Zener noise? I want to know whether to use a Zener diode or a Transistor when building a white noise generator. And FTR I intend to use Germanium because of its higher...

Ok, for the switch-on voltage of a red LED I have the readings as follows, all in volts: 1.45, 1.46, 1.46, 1.44, 1.45. The mean of these readings, in volts, is 1.45 (I rounded up to 2 decimal places as my scale reading uncertainty was +/-0.01V, and my teacher told me to round them up since to...

I create this thread to continue discussion with @jim hardy and @WWGD started elsewhere https://www.physicsforums.com/threads/any-popular-non-biased-and-reputable-sources-of-politics.827409/page-4#post-5422569 Any topic concerning computers and internet can be discussed here I don't know, but...

I got this probability question as homework, but I got very confused as I didn't know if I should calculate the balls in the 2 boxes as whole or if I should calculate the probability of the first box then add the probability of the second. Any help is appreciated. Thanks.Here is the question...

Is quantification, such as for instance with the build op of an interference pattern by individual photons, the measuring of quantum spin, or the measuring of polarized photons through a polarisation filter actually, really random, or is it possible that it might be pseudo-random?

Thank you for your time, I really appreciate it I have no idea where to even begin

A continuous random variable x has the following probability function: f(X)=(X+1)/8 -1<=X<=3 0 Otherwise 1. Find the Pr(X<=2) 2. Find the mean of X

$p(x) ={p}^{x}*{(1-p)}^{1-x}$ for $x=0.1$ $0$ otherwise Where $p$ is such that $0<=p<=1$ Question: Find the mean and variance of $X

I'm dabbling with regression (In excel), but I'm stuck because my residual plot is not normal. I have 2 variables: age, and gender(0 or 1). I regress it in excel and also plot the residuals, it is not random. In general, how do I solve this issue? If it matters, the result of my raw...

Hi All, Looking for Advice on taking Random Signals Class in the summer, I am EE student, Is it very difficult? very challenging or demanding?. I have taken classes in the summer in a community college and I have done OK(B), however I am a little unsure about this one. I work full time and have...

1.Above sentence means in 1074 mutations(Events) just one of them could make a functional protein and that mutation is beneficial? 2.Is above sentence similar to "Hoyle's calculation of the Odds of Life", thus the criticism against Hoyle's idea can apply to above sentence? Like this:

Hi, I'm trying to work out how many time a particle going on a random walk starting at the origin would pass a particular point or points for a given total number of steps. I've simulated the problem and get approximately the same answer every time, however I'm struggling to know where to even...

Hi! I'm searching for guidance and help since I don't know how to solve this problem. Here it is: a) The two-dimensional random variable (ξ,η) is uniformly distributed over the square K={(x,y): 0≤x≤1 , 0≤y≤1} . Let ζ=√ξ2+η2 me the distance between the origo and the point (ξ,η) . Calculate the...

Let $X\sim U(0,1)$ and define $Y=1-X$. What statement is TRUE? (1): $F_{X}(u)\neq F_{Y}(u)$, for every $u\epsilon \left [ 0,1 \right ]$; (2): $Y$ is not a rv; (3): $E(X+Y)=2$; (4): $Y\sim U(0,1)$; (5): none of the remaining statements.

I'm learning basic probability and have some understanding of PDF's and CDF's now. (I've not done expected values yet though so I'm not familiar with that notation). I've come across standardization of a random variable, X, which then gives a new random variable Y with the properties that Y has...

Hello. Can you help me solve it? ($F$ is a $\sigma $ algebra). Let $X$ be a rv over $(\Omega ,F,P)$. Set $Y:= min\left \{ 1,X \right \}$. What statement is TRUE? (1): $\left \{ Y=X \right \}\neq \Omega $; (2): $F_Y(x)=F_X(x)$ for every $x\epsilon \Re $; (3): $Y\leqslant X$ for every outcome...

Find the standard score for a the data value 9 from a normal distribution which has a mean of 16.8 and a standard deviation of 2.3

Hi There are so many different kinds of probability distributions regarding a uniform distribution of points on the surface or inside a hypersphere in 2D and 3D and it's hard to see the big picture or any pattern between them. I'm confused and exhausted :) The overall fuzzy plan is to go from...

Hi I created a program to run a random walk in 1d with only input the number of steps and the number of walks. I used a random number generator to produce only two outcomes (step forward and step back) and in the main function I want to calculate the average of x (over a number of walks) and...

When I pick a random number on a number line made out of integers, starting from zero and expanding infinite to the right, what can I say about the position of this random number ? To the right the amount of numbers is infinite. To the left is an amount, a number, so that is finite, but it has...

Okay, it's not easy for me but probably for you ;) Hello first of all! I have two questions: 1. Why is there a minus before the expression in the red circle? 2. How did the x((n-1)-1) in the last line come to be?More precise: I understand the first parts. It's the random walk and x signifies...

Time to split the thread again. Here is the last page of part 4. https://www.physicsforums.com/threads/random-thoughts-part-4.786642/page-201

Homework Statement Let $$ \Phi(x)=\int_{-\infty}^{x} \frac{1} { \sqrt{2\pi} } e^{-y^2 /2} dy $$ and $$ \phi(x)=\Phi^\prime(x)=\frac{1} { \sqrt{2\pi} } e^{-x^2 /2} $$ be the standard normal (zero - mean and unit variance) cummulative probability distribution function and the standard normal...

Hello! I'm struggling with a probably easy physics question concerning random walks. Here I have the slide regarding this: Delta is the distance that a particle moves. Can someone explain where the n-1 initially comes from? Does it have to do wtih the concept of the degrees of freedom? Than...

Hello, I have this question, which I think I solve correctly, but I am getting the wrong answer. X represent the point that the computer chooses on a scale of 2 to 5 (continuous scale) in a non-uniform way using the density: f(x)=C*(1+x) what is the probability P(3<X<4|X>1) ? I solved the...

Hello all I have this question I am trying to solve. In an urn there are 6 balls, numbered: 1,2,3,4,5,6. We take 4 balls outs, without replacement. X - the minimal number we see Y - the maximal number we see I need to joint distribution. I understand that X is getting the values 1,2,3 while...

I was wondering how could I check how random the random.randrange() method of python's random package (?or class?) is... How could I do that by building a macro? Maybe check the two hypothesis: is good random generator vs is not?

There is a perfect software program that can answer "everything" you ask. Can this software program predict a posible non-existent random choice (of 2 objects) in the past chosen by another perfect software program that answers competely random? The choice is completely random but it never...

Homework Statement In the argand plane z lies on the line segment joining # z_1 = -3 + 5i # and # z_2 = -5 - 3i # . Find the most suitable answer from the following options . A) -3∏/4 B) ∏/4 C) 5∏/6 D) ∏/6 2. MY ATTEMPT AT THE SOLUTION We get two points ( -3 , 5 ) & ( -5 , -3 ) => The...

Hi, Suppose there's an operation like the following: x(t) = x(t-1) + rand(m..n) with x(t) = current value x(t-1) = previous value rand(m..n) = equally distributed random real number in the range of m and n is there a way to estimate the value of x(t) after Y iteration without actually doing...

"Let X be a Bernoulli random variable. That is, P(X = 1) = p and P(X = 0) = 1 − p. Then E(X) = 1 × p + 0 × (1 − p) = p. Why does this definition make sense? By the law of large numbers, in n independent Bernoulli trials where n is very large, the fraction of 1’s is very close to p, and the...

Suppose I measure the position of a particle, and I find it to be at point C. By deterministic, I mean if we know the wave function of the measuring instrument (and of course also the wave function of the particle before measurement) then we can, in principle, know that the particle is going to...

Does the set of random integers with random lengths (the number of digits), which hypothetically would generate random numbers with random lengths for eternity, produce all possible integers? It seems to me that this is a natural conclusion but I've never seen a proof of this. A more incredible...

Hello, So I was asked this question the other day and don't really know how to go about it: "Define a random process by: Xn+1 = Xn+1 with probability 1/2 Xn+1 = 1/Xn with probability 1/2 Given that X0= 100, find the expectation of X10 " I've only ever really met random processes...

Homework Statement Hello! In our class, we just completed a lab on momentum and energy conservation in collisions. It was a computer simulation. Although, for the lab report, the teacher wants us to write the random, systematic, and human errors. Can someone describe what each error means? What...

Let ##X_i## are i.i.d. and take -1 and +1 with probability 1/2 each. How to prove ##\lim_{n\rightarrow\infty}{\sum_{i=1}^{n}{X_i} }##does not exsits (even infinite limit) almost surely. My work: I use cauchy sequence to prove it does not converge to a real number. But I do not how to prove it...

Homework Statement Supposethat X1and X2 are .random variables and that each of them has the uniform distribution on the interval [0, 1]. Find the p.d.f. of Y =X1+X2. Homework Equations Find cdf of Y and then the pdf The Attempt at a Solution the joint pdf would be f(x1,x2)= 1...

Homework Statement Given X,Y,Z are 3 N(1,1) random variables, (1) Find E[ XY | Y + Z = 1] Homework EquationsThe Attempt at a Solution I'm honestly completely lost in statistics... I didn't quite grasp the intuitive aspect of expectation because my professor lives in the numbers side and...

A number can be random even if limitations are applied to the outcome - e.g. selecting a random integer between 1 and 5 restricts the outcome to one of 5 numbers, but the outcome is still random. The same would be true of between 1 and 2; although there are heavy restrictions, an unbiased...

Is any of the conjectures in: http://arxiv.org/pdf/hep-th/9610043v3.pdf have been proven/disproven? what has been left still open? I am thinking of reading this article sometime in the future, hope it's digestable (but first need to finish my studies of QFT and GR.)

Homework Statement I have the joint cdf of two random variables X and Y and they ask me to find the cdf of just Y. I know that you just take the limit of the cdf as x->infinity, but I am just wondering if you can also do this by calculating the joint pdf and then the marginal of Y and then from...

Homework Statement Consider two random variables X and Y with joint PMF given by: PXY(k,L) = 1/(2k+l), for k,l = 1,2,3,... A) Show that X and Y are independent and find the marginal PMFs of X and Y B) Find P(X2 + Y2 ≤ 10) Homework Equations P(A)∩P(B)/P(B) = P(A|B) P(A|B) = P(A) if independent...

Homework Statement Suppose the distance X between a point target and a shot aimed at the point in a coin-operated target game is a continuous random variable with pdf f(x) = { k(1−x^2), −1≤x≤1 0, otherwise. (a) Find the value of k. (b) Find the cdf of X. (c) Compute P (−.5...

Hi, Consider model of one dimensional spin chain with a random couplings J. The Hamiltonian is the following: $$ H = \sum_i J_i (S_i^x S_{i+1}^x+ S_i^y S_{i+1}^y)$$, Which by Jordan-Wigner transformation we can transform it to the fermionic representations. $$ H = \sum_i J_j/2 (c_i...

Homework Statement X ~ Uniform (0,1) Y = e-X Find FY (y) - or the CDF Find fY(y) - or the PDF Find E[Y] 2. Homework Equations E[Y] = E[e-X] = ∫0 , 1 e-xfx(x)dx FY(y) = P(Y < y) fY(y) = F'Y(y) The Attempt at a Solution FX(x) = { 0 for x<0 x for 0<x<1 1 for 1<x } fX(x) = { 1 for...

I have been puzzled about the possible interaction mechanisms among the various particles during inflation that would have performed the mixing of mass-energy (ME) required for the uniformity of the CBR. Here is my understanding about what must happen to acheve the necessary mixing of ME during...

Hi I'm having a few conceptual difficulties with random variables and I was hoping someone could clear up a few things for me: 1) Firstly, what exactly do we mean when we say that two random variables X and Y are equal. I understand what identically distributed means, but my difficulty is with...