Question

Consider the following discrete probability mass function.

x 3 1 –1
P(X = x) 0.25 0.30 0.45

Find P(X ≥ 1).

Answer 1

Answer:

$P(x \geq 1) = 0.55$

Step-by-step explanation:

Given:

x --------------3 ---------1 ------- –1

P(X = x) --- 0.25 ---0.30 ---- 0.45

Required

Calculate $P(x \geq 1)$

$x \geq 1$ implies that x = 1,2,3,4......

So:

$P(x \geq 1) = P(x = 1) + P(x = 3)$

From the above table

$P(x = 1) = 0.30$

$P(x = 3) = 0.25$

Substitute these values in $P(x \geq 1) = P(x = 1) + P(x = 3)$

$P(x \geq 1) = 0.30 + 0.25$

$P(x \geq 1) = 0.55$