X is a random variable. Taking the values 3, 4 and 12 with probabilities \(\frac{1}{3},\frac{1}{4}\)and \(\frac{5}{12}\).Then E(X) is

(a)

5

(b)

7

(c)

6

(d)

3

Variance of the random variable. X is 4, Its mean is 2. Then E(X²) is _________

(a)

2

(b)

4

(c)

6

(d)

8

μ₂ = 20, μ¹₂ = 276 for a discrete random variable X. Then the mean of the random variable. X is _________

(a)

16

(b)

5

(c)

2

(d)

1

V(4X + 3) is _________

(a)

7

(b)

16V(X)

(c)

4V(X)

(d)

19

If E(X)  = \(\frac{1}{2}, E(X^2)=\frac{1}{4}\), then V(X) is ________

(a)

0

(b)

\(\frac{1}{4}\)

(c)

\(\frac{1}{2}\)

(d)

1