Nitin P. answered 06/28/20
Machine Learning Engineer - UC Berkeley CS+Math Grad
A plane divides 3-D space into 2 equal halves. So, a point has a 50% chance of being on either side of the plane. Therefore, the probability of being in a region bounded by 3 planes is (1/2)3 = 1/8. Note that your answer of P = 0 is actually a conditional probability, conditioning on the planes not being parallel and forming a bounded region.
Nitin P.
We don't care about the distribution of the points, because they're already fixed in space and deterministic. We care about what happens when we randomly place the planes.06/28/20