Let the observations

Question:

Let the observations $x_{i}(1 \leq i \leq 10)$ satisfy the equations,

$\sum_{i=1}^{10}\left(x_{i}-5\right)=10$ and $\sum_{i=1}^{10}\left(x_{i}-5\right)^{2}=40$. If $\mu$ and $\lambda$ are the

mean and the variance of the observations, $x_{1}-3, x_{2}-3, \ldots$

$x_{10}-3$, then the ordered pair $(\mu, \lambda)$ is equal to:

  1. (1) $(3,3)$

  2. (2) $(6,3)$

  3. (3) $(6,6)$

  4. (4) $(3,6)$


Correct Option: 1

Solution:

Mean of the observation $\left(x_{i}-5\right)=\frac{\Sigma\left(x_{i}-5\right)}{10}=1$

$\therefore \quad \lambda=\left\{\right.$ Mean $\left.\left(x_{i}-5\right)\right\}+2=3$

Variance of the observation

$\mu=\operatorname{var}\left(x_{i}-5\right)=\frac{\Sigma\left(x_{i}-5\right)^{2}}{10}-\frac{\Sigma\left(x_{i}-5\right)}{10}=3$

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