The Probability distribution of a discrete random variable X is given as :
The mean of the distribution is : |
$\frac{4}{3}$ $\frac{5}{3}$ $\frac{7}{6}$ $\frac{16}{9}$ |
$\frac{16}{9}$ |
The correct answer is Option (4) → $\frac{16}{9}$ Since, the sum of probabilities must be equal to 1. $2k^2+k^2+3k^2+k=1$ $6k^2+k-1=0$ $6k^2+3k-2k-1=0$ $3k(2k+1)-1(2k+1)=0$ $(2k+1)(3k-1)=0$ $⇒k=\frac{1}{3}$ [Always positive] ∴ Mean of distribution = $0×2×(\frac{1}{3})^2+1×(\frac{1}{3})^2+2×3(\frac{1}{3})^2+(\frac{1}{3})×3$ $=\frac{0}{9}+\frac{1}{9}+\frac{6}{9}+\frac{3}{9}=\frac{6+1+9}{9}$ $=\frac{16}{9}$ |