Correct Answer - Option 4 : 0.6
Explanation:
For discrete random variable
Mean = μ = E(x) = ∑ xP(x)
= 1 × 0.3 + 2 × 0.6 + 3 × 0.1 = 1.8
And E(x2) = ∑x2P(x) = 1 × 0.3 + 22 × 0.6 + 32 × 0.1 = 3.6
Then variance V = E(x2) – [E(x)]2 = 3.6 – (1.8)2 = 0.36
Then, standard deviation
\(= \sqrt V = \sqrt {0.36} = 0.6\)