+ Reply to Thread
Results 1 to 2 of 2

Thread: Binomial expectation E(X|X>1)

  1. #1
    Points: 6, Level: 1
    Level completed: 11%, Points required for next Level: 44

    Thanked 0 Times in 0 Posts

    Red face Binomial expectation E(X|X>1)

    General case: X~B(n,p)
    I could integrate the product of x and pmf from 1 to infinity and divide it by the integral of just pmf from 1 to infinity to find it, but I'm really stuck since I can't do it due to the sophisticated pmf function of binomial.
    How can we find this expectation and Variance(X|X>1)?
    Thank u💕

  2. #2
    Points: 2,000, Level: 26
    Level completed: 40%, Points required for next Level: 150

    New Zealand
    Thanked 48 Times in 47 Posts

    Re: Binomial expectation E(X|X>1)

    Seeing it's binomial, it is a sum to n terms, rather than an integral to infinity. Imagine the full probability table. Each x has a p, xp and x^2p. From these you can work out mean = sum of xp, and var = sum of x^2p - mean^2.
    Now we have x = 0 and x = 1 removed. For x=0 the xp and x^2p were 0 and 0, Find the values for xp and x^2p for x = 1. Find the new sum of xp and sum of x^2p and so your new mean and variance.

+ Reply to Thread


Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Advertise on Talk Stats