Find the mean deviation about the mean for the data $4, 7, 8, 9, 10, 12, 13, 17$.

The mean deviation about the median of the numbers $3x, 6x, 9x, \ldots, 81x$ is $91$. Then $|x| = $

The approximate value of the mean deviation about the mean for the following data is

Class Interval	$0-2$	$2-4$	$4-6$	$6-8$	$8-10$
Frequency	$1$	$2$	$3$	$2$	$1$

$\begin{aligned} &\text{Find the mean deviation about the mean for the following data:} \\ &\begin{array}{|l|c|c|c|c|c|} \hline \text{Class Interval} & 0-6 & 6-12 & 12-18 & 18-24 & 24-30 \\ \hline \text{Frequency} & 1 & 2 & 3 & 2 & 1 \\ \hline \end{array} \end{aligned}$

Find the mean deviation about the mean for the following data:

Height in $cm$	Number of boys
$95-105$	$9$
$105-115$	$13$
$115-125$	$26$
$125-135$	$30$
$135-145$	$12$
$145-155$	$10$

If the mean deviation about the median of $x, 2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x, 10x$ is $30$,then $|x|$ equals: