Consider the following cumulative probability distribution.



x 0 1 2 3 4 5
P(X ≤ x) 0.11 0.32 0.45 0.75 0.83 1


a. Calculate P(X ≤ 3). (Round your answer to 2 decimal places.)

b. Calculate P(X = 2). (Round your answer to 2 decimal places.)

c. Calculate P(1 ≤ X ≤ 3). (Round your answer to 2 decimal places.)

1 answer

a. P(X ≤ 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.11 + 0.32 + 0.45 + 0.75 = 1.63. Rounded to 2 decimal places, P(X ≤ 3) is 1.63.

b. P(X = 2) = P(X ≤ 2) - P(X ≤ 1) = 0.45 - 0.32 = 0.13. Rounded to 2 decimal places, P(X = 2) is 0.13.

c. P(1 ≤ X ≤ 3) = P(X = 1) + P(X = 2) + P(X = 3) = 0.32 + 0.45 + 0.75 = 1.52. Rounded to 2 decimal places, P(1 ≤ X ≤ 3) is 1.52.