Random Definition and 1000 Threads

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...

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...

Hi everyone! I'm just curious how many simple little examples of genius are realized in simple daily life. I will start with a kooky situation where I scooped a handful full of change off the table while I was in the kitchen with my wife and I noticed an unusual sound. And after some searching...

Homework Statement [/B] Consider a random experiment with a sample space S={1,2,3,⋯}. Suppose that we know: P(k) = P({k}) = c/(3^k) , for k=1,2,⋯, where c is a constant number. Find c. Find P({2,4,6}). Find P({3,4,5,⋯}) Homework Equations For any even A, P(A) ≥ 0. Prbability of the...

Homework Statement Problem Consider a random experiment with a sample space S={1,2,3,⋯}. Suppose that we know: P(k) = P({k}) = c/(3^k) , for k=1,2,⋯, where c is a constant number. Find c. Find P({2,4,6}). Find P({3,4,5,⋯}) I am primarily interested in part 1, finding C. The rest...

When I play music, or when I look at a slideshow, I like to use the random selection. I have about 1000 songs, and 25000 pictures in my libraries. Taking pictures for example, if I view 100 pictures per day, then it should be 25000/100=250 days, on the average, before I see a repetition of...

I am new to this, and not understanding discrete math very well. This is one of my week 4 discussion questions. If someone could help me apply this to a life situation so I could understand this question better, please? I am a CNC Mill machinist, and I understand programming a computerized...

None of these questions are homework problems, they're just confusing things that homework has caused 1. In math, what is the difference between a bracket and a parenthesis? Also what about the right symbols for ordered pairs , is that strictly these [ ] or these { } 2. If you have lots of...

Hello Forum, I know a little bit about how the oscilloscope works: an electron beam hits the scope screen and traces the waveform. Once the beam reaches the right side of the screen it zaps back to start tracing again. Is it possible that while the beam returns to the lefthand side of the...

It has been a very long time since I have done any calc or hard math, I hope this question is in the right place. I have a HUGE number, that is random and big. What do I need to study/look at to create a formula that will generate just it?

Hello I am wondering how can I make sure that every number which I am losing will be different? I am using the following code: program lottery implicit none real(kind=4) :: x real(kind=8) :: y integer :: i, seed= 64256 call srand(seed) do i=1,6 x=rand() ! to make the lossing interval...

I am using GNU companion ,in that i am not able to plot random source which i am giving as bytes . how to plot in a sink?

Consider the following random walks in 2D, starting at a point we will call the origin: (a) random walk on a square lattice (step size 1 on the integer lattice for example) (b) random walk on a triangular lattice (step size 1 on the lattice of equilateral triangles of side 1). Thus there are 6...

Sorry, I know this is probably the wrong place to ask this question, but where in this forum can we start threads to share and discuss random physics and math news?

This might be a silly question but when people say that something on the quantum level is completely "random," (except for general probability) does that mean, according to theory at least, if you were to go back in time and repeat an experiment exactly that the results could just as easily be...

In the Stoner-Wohlfarth model, a uniaxial, non-interacting particle is cooled to very low temperature with no exposure to an external field. Therefore, the orientation of each particle is random, if you have a group of particles. In their paper, they integrate such that: \langle \cos (\Theta...

I was reading a post on Facebook about cleaning and it said to mix rubbing alcohol and vinegar and put it in your windown washer fluid tank. Someone commented that it would corrode or eat away at the tubing. I keep thinking the mixture would be an acid /base mixture and would neutralize. I was...