Question

Which one of the following is not correct for a discrete probability distribution:
A) P(X > 4) = 1 – P(X < 5)
B) P(X ≥ 4) = 1 – P(X ≤ 3)
C) P(X ≥ 4) = 1 – P(X < 4)
D) P(X ≥ 4) = 1 – P(X < 3)

Answer 1

I think it might be A because -(Px < 5) might create values < 0???
but I am not sure how to evaluate these P( ) formulas.

Answer 2

what do they mean by
P(X > 4)
and
P(X < 5) ???

Answer 3

okay I think P(X <4) might mean the probability that x < 4

Answer 4

okay I think then it must be D, because if X <3 then X = 2.x or less...
and P(x>=-4) ignores the whole range of 3.

Answer 5

hint:
the probability function has to be normalized, namely sum of probabilities has to be equal to \(1\), for example we have this:

when I write \(P(x>4)\) I mean the area under the curve for all x such that \(x<4\),