In: Statistics and Probability
Let (Ω, F , P) be a probability space. Suppose that Ω is the
collection of all possible outcomes of a single iteration of a
certain experiment. Also suppose that, for each C ∈ F, the
probability that the outcome of this experiment is contained in C
is P(C).
Consider events A, B ∈ F with P(A) + P(B) > 0. Suppose that the
experiment is iterated indefinitely, with each iteration identical
and independent of all the other iterations, until it results in an
outcome that is an element of A ∪ B, after which it stops. What is
the probability that this procedure results in an outcome that is
an element of A? Do not use conditional probability to answer this
question.