If x_1, x_2, x_3, ldots, x_n are n observatio | vedclass

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(A) Given that $\sum(x_i+2)^2 = 28n$ $\Rightarrow \sum x_i^2 + 4\sum x_i + 4n = 28n$ $\Rightarrow \sum x_i^2 + 4\sum x_i = 24n$ $... (i)$ Similarly,$\

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$12$

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(A) Given that $\sum(x_i+2)^2 = 28n$ $\Rightarrow \sum x_i^2 + 4\sum x_i + 4n = 28n$ $\Rightarrow \sum x_i^2 + 4\sum x_i = 24n$ $... (i)$ Similarly,$\sum(x_i-2)^2 = 12n$ $\Rightarrow \sum x_i^2 - 4\sum x_i + 4n = 12n$ $\Rightarrow \sum x_i^2 - 4\sum x_i = 8n$ $... (ii)$ Adding $(i)$ and $(ii)$: $2\sum x_i^2 = 32n \Rightarrow \sum x_i^2 = 16n$ Subtracting $(ii)$ from $(i)$: $8\sum x_i = 16n \Rightarrow \sum x_i = 2n$ The variance is given by $\sigma^2 = \frac{\sum x_i^2}{n} - \left(\frac{\sum x_i}{n}\right)^2$ $\sigma^2 = \frac{16n}{n} - \left(\frac{2n}{n}\right)^2 = 16 - 4 = 12$

$C$.$I$.	$75$-$175$	$175$-$275$	$275$-$375$	$375$-$475$	$475$-$575$	$575$-$675$	$675$-$775$
$f_i$	$3$	$2$	$1$	$0$	$1$	$2$	$3$

Class Interval	Frequency
$0 - 6$	$10$
$6 - 12$	$8$
$12 - 18$	$6$
$18 - 24$	$4$
$24 - 30$	$2$

If $x_1, x_2, x_3, \ldots, x_n$ are $n$ observations such that $\sum(x_i+2)^2 = 28n$ and $\sum(x_i-2)^2 = 12n$,then the variance is:

Similar Questions

Consider the following frequency distribution:
$C$.$I$. $75$-$175$ $175$-$275$ $275$-$375$ $375$-$475$ $475$-$575$ $575$-$675$ $675$-$775$
$f_i$ $3$ $2$ $1$ $0$ $1$ $2$ $3$
If the variance of this distribution is $60000$,then the coefficient of variation of the distribution is:

The variance of the following frequency distribution is
Class Interval Frequency
$0 - 6$ $10$
$6 - 12$ $8$
$12 - 18$ $6$
$18 - 24$ $4$
$24 - 30$ $2$

Find the mean and variance of the frequency distribution given below:
$\begin{array}{|l|l|l|l|l|} \hline x & 1 \leq x < 3 & 3 \leq x < 5 & 5 \leq x < 7 & 7 \leq x < 10 \\ \hline f & 6 & 4 & 5 & 1 \\ \hline \end{array}$

The mean of a set of $10$ observations is $5$ and the standard deviation is $2\sqrt{6}$. If the mean of another set of $20$ observations is $5$ and the standard deviation is $3\sqrt{2}$,what is the standard deviation of the combined set of $30$ observations?

If the mean of the discrete distribution $8, 9, 6, 5, x, 4, 6, 5$ is $6$,then its standard deviation (nearest to two decimal places) is

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