Question

A random variable X has the probability distribution:

X = x	–2	–1	0	1	2
P(X = x)	4b	5b	2b	b	2b

Then the value of P(X < 1) is ______.

विकल्प

• `1/7`

• `5/7`

• `1/5`

• `5/14`

Answer 1

A random variable X has the probability distribution:

X = x	–2	–1	0	1	2
P(X = x)	4b	5b	2b	b	2b

Then the value of P(X < 1) is `5/7`.

Explanation:

Since, `sum_(x = -2)^2 "P"("X" = x)` = 1

4b + 5b + 2b + b + 2b = 1

⇒ 14b = 1

⇒ b = `1/14`

Now, P(X < 1)

= P(X = –2) + P(X = –1) + P(X = 0)

= 3b + Sb + 2b

= 10b

= `10(1/14)`

= `5/7`