0
$\begingroup$

Suppose i have a discrete random variable A such that:

  • $p(A=-1) = 3/4$
  • $p(A=0) = 1/8$
  • $p(A=1) = 1/8$

Now, i create a random variable $B = |A|$ and so

  • $p(B=0)= 1/8$
  • $p(B=1)= 7/8$

I want to compute $f_{A,B}(a,b)$ [generalized joint probability density function, using delta dirac function since it is a discrete case].

Are those variables independent so can I do $f_{A,B}(a,b)=f_A(a)\cdot f_B(B)$? Or, if they are dependent, when calculating $P(a_i,b_n)$ should i do $P(a_i,b_n) = P(A=a_i)\cdot P(B=b_n\mid A=-1)$ just like in Bayes Theorem ?

Thanks in advance.

  • 0
    *the generalized joint probability density function*... Meaning? // *You said the sum of {-1,1}, {0,0} and {1,1}*... Nope, I did not say that (and I do not know what it is that you call *the sum of {-1,1}, {0,0} and {1,1}*).2012-12-07

0 Answers 0