Question

(a) Fill in the tavle below to complete the proability distrubution of X

x 1 2 3 4
P(x) 0.3 0.2 ? 0.4
(b) compute the mean of random variable x

Answer 1

2.6

Explanation:

Given :

x 1 2 3 4

P(x) 0.3 0.2 ? 0.4

Σp(x) = 1

Hence, 0.3 + 0.2 +? + 0.4 = 1

0.9 +? = 1

? = 1 - 0.9

? = 0.1

For the mean :

E(X) = ΣX*P(X)

(1 * 0.3) + (2 * 0.2) + (3 *0.1) + (4* 0.4)

0.3 + 0.4 + 0.3 + 1.6 = 2.6

Hence, the mean = 2.6