1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Bernoulli random variable problem

  1. Apr 3, 2010 #1
    1. The problem statement, all variables and given/known data

    Suppose we want to estimate a binomial proportion, p. We take a sample of size n and count X successes.

    Consider a Bernoulli random variable, Y that is 1 with probability p and 0 otherwise. Show that the mean and variance of Y are p and p(1-p), respectively.



    2. Relevant equations



    3. The attempt at a solution
    Not too sure what to do here. I know that the mean is calculated by [tex]\Sigma[/tex]xf(x) and variance is E(X-mean)2
     
  2. jcsd
  3. Apr 3, 2010 #2

    rock.freak667

    User Avatar
    Homework Helper

    Well write out your sample space


    y 0 1
    P(Y=y)


    For y=p, your probability is?

    and in any other case such as y=0, the probability is?

    Then you just use your definition E(Y)=∑all y y P(Y=y)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook