For the probability distribution Then the $\operatorname{Var}(\mathrm{X})$ is (Given : $\left.(0.25)^2=0…

For the probability distribution
Then the $\operatorname{Var}(\mathrm{X})$ is (Given : $\left.(0.25)^2=0.0625,(0.35)^2=0 \cdot 1225,(0.45)^2=0 \cdot 2025\right)$
  1. 0.8275
  2. 1.1225
  3. 1.8275
  4. $2 \cdot 0725$

Solution

$\begin{aligned} E(X)= & (-2)(0.1)+(-1)(0.2)+0(0.2)+(1)(0.3) \\ & +2(0.15)+3(0.05) \\ = & -0.2-0.2+0+0.3+0.3+0.15 \\ = & 0.35\end{aligned}$ $\begin{aligned} \therefore \quad \operatorname{Var}(\mathrm{X}) & =\mathrm{E}\left(\mathrm{X}^2\right)-[\mathrm{E}(\mathrm{X})]^2 \\ & =(-2)^2(0.1)+(-1)^2(0.2)+0^2(0.2) \\ & +1^2(0.3)+2^2(0.15)+3^2(0.05)-(0.35)^2 \\ & =0.4+0.2+0+0.3+0.6\end{aligned}$ $\begin{aligned} & =1.95-(0.35)^2 \\ & =1.95-0.1225 \\ & =1.8275\end{aligned}$

Asked in: MHT CET 2024 (03 May Shift 2)

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