Hi I'm having a hard time wrapping my head around this particular problem.
Suppose the lifetime of a shirt bought from Sears, in days, is a non-negative random variable $L$ with probability mass function $p(n) = 2^{-n}$ for $n = 1,2,...$ and $p = 0$ otherwise. What is the conditional probability mass function of $L$ given that $L > n$
Is the answer not 0?
$p_{L}(n | L > n) = Pr(L = n | L > n) = \frac{Pr(L = n \cap L > n)}{Pr(L > n)} = 0$, L cannot be equal to n and be greater than n.
Thanks for your help.