Using the table, find the probability that X is greater then 1.?

Question

X P(X)
0 0.1
1 0.2
2 ?
4 0.3
6 0.3

Answer 1

The sum of all the probabilities should be 1.0, and all of the entries add up to 0.9, so the missing number beside 2 is 0.1.

The probability that X is greater than 1 is the sum of probabilities for all entries in the table greater than 1 (2 [0.1], 4 [0.3], 6 [0.3]), which is 0.7.

Answer 2

P(X > 1) = 1 - P(X = 0 or 1) = 1 - P(X = 0) - P(X = 1) = 1 - 0.1 - 0.2 = 0.7.

Answer 3

P(X > 1) = 1 - P(X ≤ 1)
= 1 - (0.1 + 0.2)
= 1 - 0.3
= 0.7