Probability, Probability Theory, Random Variable, Probability Distributions, Mathematics.
die, with possible outcomes of {1,2,3,4,5,6}, where we are interested in the probability of rolling anything below a three, P(X < 3). The only possible values for this condition are 1 and 2. Therefore, P(X < 3) must include both the possibility of rolling a 1 and rolling a 2, which is the sum from