Poisson Definition and 441 Threads

  1. P

    Solving a Probability Question with Poisson Distribution

    Homework Statement I am solving a particular probability question using Poission distributin after the Solving I get an equation Homework Equations 1.67 = e^-a (1/1-a) I ought to get the value of a from the equation but I was Unable to go further from here . The Attempt at a...
  2. T

    Suppose X and Y are independent Poisson random variables,

    Suppose X and Y are independent Poisson random variables, each with mean 1, obtain i) P(X+Y)=4 ii)E[(X+Y)^2] I m trying to solve this problem but have difficulty starting ... If some one could give me a some pointers
  3. T

    If X and Y are independent poisson variates

    Question: If X and Y are independent poisson variates with mean λ1 and λ2 respectively, what is the probability that i) X + Y =k ii) X = Y Solution: Dont know how to solve this .
  4. T

    Poisson errors for the distribution of galaxies?

    Poisson errors for the distribution of galaxies?? Hi, I have some data regarding the distribution of galaxies of varying mass in different density regions of the Universe, from which I have a mass functions for each region. I would now like to introduce some errors so I can determine whether...
  5. Q

    Proof of Poisson: Proving P_t Not in {0,1}

    How can I prove that P( there exist a t>0 : the changeP_t is not in {0,1} ) = 0 where (P_t)_t>0 is a piosson Proces with parameter lambda > 0. Thank you.
  6. M

    Practical use of binomial and Poisson Distribution in the field of engineering

    Hi... Hope i 'll get the good result that where we practically use the binomial and poisson distribution in the field of engineering...
  7. K

    How do I evaluate this Poisson distribution?

    Homework Statement How do I evaluate this Poisson distribution? Homework Equations The Attempt at a Solution So I have figured out what the values for lambda and x are, but I don't know how to evaluate once I plug the values into the formula. λ = 20 x = 18 = [ e^-20...
  8. T

    Probability question; Conditional probability and poisson distribution

    Homework Statement A radioactive source emits particles according to a Poisson process, at an average rate of λ per unit time. Each particle emitted has probability p of being detected by an instrument, independently of other particles. Let X be the number of particlese emitted in a given...
  9. F

    Independence in Poisson Process

    I'm studying the Poisson Process (rate R) and I'm hung up on the issue of dependence. This seems like and easy question but I have no background in probability whatsoever. By definition, the number of events in disjunction time intervals are independent. Okay. Fine. But say we have an...
  10. R

    Poisson approximation to the normal

    So my book merely mentions that this holds as a result of the central limit theorem for values of lambda greater than 10, but ideally greater than 32. Anyway I was wondering if anyone knew this actual proof as I am interested in seeing it step by step and I could not have found it anywhere...
  11. S

    Probability of event occurring - poisson distribution?

    probability of event occurring -- poisson distribution? I am the keeper of records for my local Volunteer Fire Dept. I have now collected data for each of our incident calls from the last 3 years and have made some _very_ basic stabs at interesting statistics which you can see at...
  12. Z

    How to Calculate Crime Probability Using Poisson and Binomial Distributions?

    Hey guys, I'm kind of stuck on this question. In a certain town, crimes occur at a Poisson rate of 2.4 per month (i.e. according to a Poisson process with a rate of 2.4 per month). What is the probability of having exactly 2 months (not necessarily consecutive) with exactly 4 crimes during...
  13. snoopies622

    Poisson Brackets: A Simple Example in Classical Mechanics

    Could someone show me a simple example of the usefulness of Poisson brackets - for instance, a problem in classical mechanics? I know the mathematical definition of the Poisson bracket, but from there the subject quickly seems to get very abstract.
  14. T

    Calculating Poisson Probability for Car Rental Income

    Homework Statement A car rental shop has four cars to be rented out on a daily basis at $ 50 per car. The average daily demand for cars is four. (1) Calculate the expected daily income received from the rentals (2) If the shop wishes to have one more car, the additional cost incurred...
  15. Y

    Help with Poisson problem in a unit ball.

    I cannot get the answer of the problem as in the book but the book usually right. I did it in 2 totally different ways and I still get my own answer. Can anyone help me double check? This is to find u(r,\theta,\phi) given: \nabla^2 u(r,\theta,\phi) = -k u(r,\theta,\phi) = f(r)=1 \hbox {...
  16. K

    The quadratic covariation of Brownian motion and poisson process

    Hi: I want to know the quadratic covariation of Brownian motion B(t) and poisson process N(t).Is it B(t)? Thanks !
  17. Saladsamurai

    Probability Poisson Process and Gamma Distribution

    Homework Statement The Attempt at a Solution Part (a) is no problem, it is simply P(X>10) = 1 - P(X<=10) which requires the use of tabulated cumulative poisson values. Part (b) is throwing for a loop. I know that I need to invoke the Gamma distribution since that is what the...
  18. Y

    I don't agree with the solution manual of a mixed poisson problem

    Homework Statement Solve mixed poisson's problem on disk given \nabla^2 U= r sin \theta \hbox{ for } 0 <r< \frac{1}{2} \nabla^2 U= 0 \hbox{ for } \frac{1}{2} < r < 1 With given boundary condition U(1,\theta)=0 2. Answer from the solution manual U(r,\theta) =...
  19. A

    Poisson Process Conditonal Probabilities

    Hey I'm really struggling with this: What is the expected value of a poisson process (rate λ, time t) given that at least one even has occured? I was told the best way was to find the conditional distribution first. So this is: P(Xt=z | Xt≥1) = P(Xt=z, Xt≥1) / (PXt≥1) = P(Xt=z) /...
  20. V

    Calc Poisson Bracket: {π,∂φ} Calculation

    How can I work out {π,∂φ} where {,} is a Poisson Bracket; π is the canonical momentum and ∂φ is the spatial derivative of the field (ie. not including the temporal one). Basically the question boils down to (or atleast I think it does!), working out ∂(∂φ) /∂φ - ie. differentiating the...
  21. D

    Random Processes | Poisson or not? | Probability of doing n jobs in t hours

    Homework Statement The number of hours that it takes to process a certain type of job is a random variable with mean and standard deviation 2. AAssuming that processing times are independent, approximate the probability that atleast 50 jobs can be sequentially processed within 240 hours...
  22. D

    Stochastic Processes, Poisson Process | Expected value of a sum of functions.

    Homework Statement Suppose that passengers arrive at a train terminal according to a poisson process with rate "$". The train dispatches at a time t. Find the expected sum of the waiting times of all those that enter the train. Homework Equations F[X(t+s)-X(s)=n]=((($t)^n)/n!)e^(-$t))...
  23. R

    No Poisson Ratio for Link Element in FEA

    in finite element analysis there is no poisson ratio for LINK ELEMENT (truss structure) just explain ?
  24. L

    Statistics Question: The 3rd Moment of Poisson Distribution

    Homework Statement X is a discrete random variable that has a Poisson Distribution with parameter L. Hence, the discrete mass function is f(x) = L^{x} e^{-L} / x!. Where L is a real constant, e is the exponential symbol and x! is x factorial. Without using generating functions, what is...
  25. Y

    Solving 2D Poisson problem with a single series

    Solving 2D Poisson problem with a single series! Conventional solution of \nambla^2u(x,y)=f(x,y) involve solution u(x,y)= \sum_{n=1}^{\infty} \sum_{m=1}^{\infty}E_{mn} sin(\frac{m\pi}{a}x) sin(\frac{n\pi}{a}y) This is a two series solution which is tedious to solve. The book PDE by Asmar...
  26. S

    Probability Question About The Poisson Probability Distribution

    Probability Question About "The Poisson Probability Distribution" Homework Statement - Assume that 1 in 200 people carry the defective gene that causes inherited colon cancer. A sample of 1000 individuals is taken. Use the Poisson approximation to calculate the appoximate standard deviation...
  27. M

    Validating the Probability Function f(x) for Zero-Inflated Poisson Distribution

    Homework Statement f(x) = (1-p)+pe^-lamdba ; x=0 = [p(e^-lambda)lambda^x]/x! ; x = 1, 2, ... = 0 ; otherwise Homework Equations show that f(x) is a valid probability function The Attempt at a Solution I think I am supposed to integrate...
  28. 8

    A poisson distribution question

    Homework Statement On average, each of the 18 hens in my henhouse lays 1 egg every 30 days. If I check the hens once per day and remove any eggs that have been laid, what is the average number, μ, of eggs that I find on my daily visits? What is the most probable (whole) number of eggs that I...
  29. E

    Poisson Probability Distribution

    Homework Statement Suppose that .10% of all computers of a certain type experience CPU failure during the warranty period. Consider a sample of 10,000 computers. a.)What are the expected value and standard deviation of the number of computers in the sample that have the defect? b.) What...
  30. D

    What is the Probability of 2 Events Occurring in a Poisson Process?

    Homework Statement Events X, Y, Z are all Poisson processes. Event X has a rate of 1 per unit time , event Y has a rate of 2 per unit time and event Z has a rate of 3 per unit time. Find the probability that 2 events (of any type) occur during the interval (0, 3). Homework Equations...
  31. R

    Probability of 1st Arrival From Poisson Process of Rate $\lambda$

    I did this question, but I'm unsure of my reasons behind it. I was hoping someone here could go through the problem for me. I got the answer 1/\lambda - 1/(\lambda + \mu). I did so by integrating, \int_0^\infty P(\text{one event from } \lambda \text{ in }(0, t]) \times P(\text{zero event...
  32. P

    Graph analysis - how closely histogram fits poisson curve

    Homework Statement Its about random radioactive decay. I have a histogram showing the number of counts recorded in 3 second intervals and I've drawn the Poisson Curve on the same graph. I have a graph for 50 intervals and one for 100 intervals and I need to analyse how well the data...
  33. P

    Poisson dist. with small numbers

    Dear Physicists, I have a poisson dist with a mean at 0.00107. I tried that usual SQRT(mean) for the standard deviation but of course I got an sigma larger than my actual plot. Can someone point me to some text or the right theory? Cheers L
  34. R

    Poisson Martingales and Gambler's Ruin

    I posted this in the HW help section, but I had no responses. I figure that this place may be better to answer this question. If this is against the rules or anything, mods please remove it! Homework Statement Find the probability of an outcome of Gambler's Ruin using a Poisson...
  35. R

    Quadratic Variation of a Poisson Process?

    Hey guys, This is my first post on PhysicsForums; my friend said that this was the best place to ask questions about math. Anyways, I have to find the Quadratic Variation of a Poisson Process. My professor doesn't have a class textbook (just some notes that he's found online), and...
  36. P

    Definition of Poisson Bracket: {f,g}

    Hi, what is the correct definition for a Poisson bracket? Some books say it is: {f,g} = df/dp.dg/dq - df/dq.dg/dp but others say it is: {f,g} = df/dq.dg/dp - df/dp.dg/dq One is the other multiplied by -1. Which is the correct definition? Thanks for any help.
  37. B

    Poisson Statistics in Solid State Physics

    Homework Statement In the Drude model the probability of an electron having a collision in an infinitesimal time interval dt is given by dt/\tau. (a) Show that an electron picked at random at a given moment will have no collisions during the next t seconds with probability e-t/\tau. (b) Show...
  38. K

    Poisson and binomial distributions, corrupted characters in a file

    A text file contains 1000 characters. When the file is sent by email from one machine to another, each character (independent of other characters) has probability 0.001 of being corrupted. Use a poisson random variable to estimate the probability that the file is transferred with no errors...
  39. P

    Probability of Poisson Distribution: Nr of Customers in Shop

    Nr of customers arriving at a shop follow Poisson. In 15, an average of 4 customers arrive. a) A customer has just arrived. Then a minute passed and no one arrived. What is the probability of it takoing at least 5 more min. until another customer arrives? b) Consider 40 non-overlapping...
  40. N

    Estimating the Mean for a Batch of 50 Items Using the Poisson Distribution

    A machine on average produces 4 defective items out of a batch of 100 items. Find the probability that a batch of 50 items has 3 defective items in it using the Poisson probability distribution. the problem is.. i just want to know the mean or average value for batch of 50 items.. i got...
  41. K

    Poisson process: compute E[N(3) |N(2),N(1)]

    note: N(t) is the number of points in [0,t] and N(t1,t2] is the number of points in (t1,t2]. Let {N(t): t[FONT=Times New Roman]≥0} be a Poisson process of rate 1. Evaluate E[N(3) |N(2),N(1)]. If the question were E[N(3) |N(2)], then I have some idea... E[N(3) |N(2)] =E[N(2)+N(2,3]...
  42. H

    Proof of Normal approximation to Poisson.

    I have been looking for a proof of the fact that for a large parameter lambda, the Poisson distribution tends to a Normal distribution. I know the classic proof using the Central Limit Theorem, but I need a simpler one using just limits and the corresponding probability density functions. I was...
  43. E

    Poisson distribution (would you please verify?)

    Homework Statement 1. Suppose that the number of telephone calls an operator receives from 9:00 to 9:05 A.M. follows a Poisson distribution with mean 3. Find the probability that the operator will receive: a. no calls in that interval tomorrow. b. three or more calls in that interval the...
  44. N

    Proving Poisson Brackets Homework Statement

    Homework Statement f(p(t),q(t)) = f_o + \frac{t^1}{1!}\{H,f_o\}+\frac{t^2}{2!}\{H,\{H,f_o\}}+... Prove the above equality. p & q are just coords and momenta How do we do this if we don't know what H is? Where do we start? Homework Equations The Attempt at a Solution
  45. D

    How to Determine Scalar Potential Inside and Outside a Charged Sphere?

    Homework Statement Use Poisson's equation and Laplace's equation to determine the scalar potential inside and outside a sphere of constant charge density po. Use Coulomb's law to give the limit at very large r, and an argument from symmetry to give the value of E at r=0. Homework...
  46. R

    Poisson Distribution and Chebyshev's Inequality

    Homework Statement LEt X have a Poisson distribution with u=100. Use Chebyshev's inequality to determine a lower bound for P(75<x<125) Homework Equations Chebyshev's Inequality. The Attempt at a Solution I'm really unsure of how to go about calculating this problem. Any help...
  47. M

    Independent poisson random variables

    Homework Statement There are two urns, A and B. Let v be a random number of balls. Each of these balls is put to urn A with probably p and to urn B with probability q = 1 - p. Let v_a and v_b denote the numbers of balls in A and B, respectively. Show that random variables v_a and v_b are...
  48. Q

    Using Poisson Approximation to Compare Infection Rates in Village A and B

    There are 60 infections in village A per month and 48 infections in village B per month. Let A be no of infections in village A per month and B be no of infections in village B per month. Assume occurrence is independent and random. So Method 1 (Working method): A~Po (60) and B~Po (48)...
  49. N

    Poisson Distribution: finding the MEan

    A store opens at 8 in the morning. from 8 until 10 customers arrive at poisson rate 6 per hour. Between 10 and 12 they arrive at a poisson rate of 10 per hour. From 12 to 2, the store closes for lunch, Finally from 2 to 5 the arrival rate drops linearly from 10 per hour at 2 to four per hour at...
  50. L

    Where can I find a covariant approach to Poisson brackets?

    i am searching for a detailed discussion on the relativistic poisson brackets. where i can found it?
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