....... is a branch of Mathematics in which the extraction of meaningful information is studied.

If the mode of the observations $5, 6, 8, 9, 6, 7, 8, 9, 4, 5, 8, 9, x$ and $10$ is $9$,then $x = $ ............

To draw a histogram to represent the following frequency distribution:

Class interval	$5-10$	$10-15$	$15-25$	$25-45$	$45-75$
Frequency	$6$	$12$	$10$	$8$	$15$

The adjusted frequency for the class $25-45$ is:

Three coins were tossed $30$ times simultaneously. Each time the number of heads occurring was noted down as follows:
$0, 1, 2, 2, 1, 2, 3, 1, 3, 0,$
$1, 3, 1, 1, 2, 2, 0, 1, 2, 1,$
$3, 0, 0, 1, 1, 2, 3, 2, 2, 0$
Prepare a frequency distribution table for the data given above.

Find the number of observations,if the sum of some observations is $975$ and their mean is $32.5$.

If $\bar{x}$ is the mean of $x_{1}, x_{2}, \ldots, x_{n},$ then for $a \neq 0,$ the mean of $a x_{1}, a x_{2}, \ldots, a x_{n}, \frac{x_{1}}{a}, \frac{x_{2}}{a}, \ldots, \frac{x_{n}}{a}$ is