Question

A random variable X bas the following probability distribution: 

X = x	0	1	2	3
P(X = x)	2a	3a	4a	a

The value of P (X > 0) is 

Options

• 0.9

• 0.6

• 0.8

• 0.7

Answer 1

0.8

Explanation:

Since `sum_(x= 0)^3`P(X = x) = 1,

2a + 3a + 4a + a = 1

⇒ 10 a = 1

⇒ a = `1/10`

Now, P(X > 0)

= P(X = 1) + P(X = 2) + P(X = 3)

= 3a + 4a + a

= 8a = `8 (1/10) = 0.8`