distributions

  1. Q

    Bionomial Probability Distributions

    51% of men consider themselves professional baseball fans. You randomly select 10 men and ask each if he considers himself a professional baseball fan. Find the probability that the number who consider themselves baseball fans is (a) exactly five, (b) at least six, and (c) less than four (a)...
  2. R

    a question about 'properties of multivariate normal distributions'

    hello guys, i have a question and looking for an answer quickly... :) question; prove that, Z is a vector. thank you.
  3. L

    Adding probabilities of normal distributions

    I have 2 questions on the topic of adding together probabilities. see bold text: Example: So if you have 3 stochastic variables with their own normal distribution A; B; C. Let's say they represent the percipitation per month in 3 different locations. A = N(25;4) B = N(26;7) C = N(23;3)...
  4. U

    Distributions for data with a gradient

    Hi guys, Firstly, apologies for the thread title - I couldn't think of a good way of explaining this. With reference to the data above (which is just made up numbers for this example), I was wondering how I would determine the 5th and 95th (or whatever) percentiles at any given value on the...
  5. rebirth61213

    Geometric distributions.

    Question I am struggling on is attached. I can do all the questions bar the last one; apparently, P(X=3) (where X has a geometric distribution) is incorrect. I can't really see why this is as P(X=3) is defined as 'the probability of failing two times and then having a success on the third...
  6. G

    Expectations of conditional distributions

    I've been assigned an assignment question, and am unable to finish it as I can't find anything similar for reference: Let a > 0 be given, let X ~ G(a, theta) given theta, and let theta ~ Exp(lambda). Find the conditional distribution for theta|x. Then calculate E(theta|x=4) for the case when a=2...
  7. M

    Marginal distributions (and marginal density), three variables

    I would like some help with this exercise, because I'm not completely sure about the difference between the distribution function and the density function in this context, and there is no solution in my book so I would like to know if I'm correct or not, since it is a pretty important part of...
  8. U

    How to solve vectors in distributions

    Hi, First post here, so go easy on me please! I wasn't sure where best to place this topic, but as this is the area I'm trying to learn I figured it would be better here. Basically I don't really understand how to solve a function which contains some vectors. Details below: f(x1, x2) =...
  9. P

    Matching moments of distributions of a random variable x and a transformation x1=x^2

    My statistics have become a bit rusty. I am puzzled with a problem. Let assume that x is a random variable and can either x ~ Normal(0,1) or x ~ Uniform(a,b) From Normal : E(x) = 0, V(x) = 1 From Uniform : E(x) = 1 / (a+b), V(x) = 12 / ( (b-a)^(2) ) If we want to match the mean and the...
  10. S

    Distributions kind of like complex numbers?

    I've been going through this (pretty damn awesome) lecture series, and I was wondering if someone might help me out with a thought I had at the end of lecture 12: https://www.youtube.com/watch?v=MQ_qTG7dcJQ&index=12&list=PLB24BC7956EE040CD At about 50:50 professor Osgood addresses how ordinary...
  11. M

    Normal and negative binomial distributions

    Here's the question: In a production lot of steel beams, the length of a certain type of steel beam is normally distributed with mean 10 feet and standard deviation 0.25 feet. What is the probability that we need to randomly select less than three steel beams to have the first steel beam which...
  12. T

    Discrete Distributions

    I'm told only that Y is a discrete random variable and that its mean = 2 and variance = 4 to find true and false statements for any case. How am I supposed to know which distribution formulas to use, like uniform or binomial or geometric because they have separate mean and variance equations...
  13. A

    Distributions of funcation of random variables

    Draw 15 cards at random and without replacement form a pack of 25 card numbered 1,2,3,...,25. Find the probability that 10 is the median of the card selected. Need help
  14. L

    Binomial distributions in evolutionary game theory

    Hello, im trying to figure out how the author in the attachment got from 6.37 to 6.39, especially since -when you use his equality in 6.38 - your binomial coefficient does not fit your sum anymore. Can anybody help?
  15. H

    Probability Distributions

    Hi all.... Just wanna ask: May we get the mean/expectation from a graph of probability distribution function (p.d.f.), continous random variables. (without using the formula of integration, but using the area formula) Can u show me the step to get the mean?
  16. D

    help with laplace (double exponential distribution)?

    Im trying to work ahead in my stats class and we were given a worksheet on laplace distribution. some of the given info is.. calculate the probability that an observation from a sample ofexponentially distributed observations is identified as an outlier. Set μ = 0 andβ = 1 to simplify...
  17. J

    Geometric distributions

    Howdy :) I am trying to solve but unsure of what I should be doing for part (ii). I have worked out p and the probability generating function of X for part (i). Is this information meant to help me for part (ii)? As I am unsure how I get to the point of deciding what the probability...
  18. D

    Discrete probability distributions

    Here's the question: Given X is a discrete random variable. E(X-2) = 1/3 , VAR(X-2) = 20/9 . Detrmine value of E(X^2) the ans is 23/3 . but i ended up getting 3 . why i am wrong?
  19. I

    Probability Distributions and Predicted Values

    WILL +REP AND THANK ALL WHO HELP! There is an example for this problem, but like, it does not show an example of how to spit out all of these combinations.. it suggests using the tree diagram, but I don't really think the tree diagram would help... So the example with the full solution is...
  20. S

    Looking for a reference for advanced probability distributions

    Hello all, I am looking for a reliable reference which gives the basic properties of as many standard distributions as possible. I have tried google and wikipedia with no luck. By "basic properties" i mean things like: PDF CDF MGF Mean, Variance Skewness, Kurtosis, etc The maximum likelihood...