If $x_1, x_2, ..., x_n$ are $n$ observations such that $\sum_{i=1}^n x_i^2 = 400$ and $\sum_{i=1}^n x_i = 100$,then which of the following is a possible value of $n$?

The raw data $x_1, x_2, \ldots, x_{n}$ is an $A$.$P$. with common difference $d$ and first term $0$. If $\bar{x}$ and $\sigma^2$ are the mean and variance of $x_{i}, i=1, 2, \ldots, n$,then $\sigma^2$ is:

Let $v_1$ be the variance of $\{13, 16, 19, \dots, 103\}$ and $v_2$ be the variance of $\{20, 26, 32, \dots, 200\}$. Then the ratio $v_1 : v_2$ is:

If the total number of observations is $n = 20$,$\sum x_i = 1000$ and $\sum x_i^2 = 84000$,then the variance of the distribution is

For the following frequency distribution,the variance is approximately equal to

Class Interval	$0$-$5$	$5$-$10$	$10$-$15$	$15$-$20$	$20$-$25$
Frequency	$4$	$1$	$10$	$3$	$2$

If the variance of the numbers $2, 3, 11$ and $x$ is $\frac{49}{4}$,then the values of $x$ are