Chapter 2 Random Variables

[DenisAmbrosov]

What does it mean: 'where R(x) denotes the possible realizations rendered from the random variable X'?

 

[David Harper CFA FRM]

If the random variable characterized a six-sided die such that the possible realizations are {1, 2, 3, 4, 5, 6} then here R(X) includes that set because if we want a CDF Pr(X ≤ 3) then technically we want the sum of Pr(X = 1) + Pr(X = 2) + Pr(X = 3) but we don't want to include Pr(X = 0) or Pr(X = -1) because they are not possible realizations rendered from the random variable.