The mean deviation from the mean of the data given below is

$\text{Marks}$	$10$	$15$	$20$	$25$	$30$
$\text{Number of students}$	$2$	$4$	$6$	$8$	$5$

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

Find the mean deviation about the median for the following data: $3, 9, 5, 3, 12, 10, 18, 4, 7, 19, 21$ (in $.27$)

In a series of $3n$ observations,if $n$ observations are equal to $a$ and the remaining $2n$ observations are equal to $-2a$,then the mean deviation of the observations about their mean is:

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

Income per day	Number of persons
$0-100$	$4$
$100-200$	$8$
$200-300$	$9$
$300-400$	$10$
$400-500$	$7$
$500-600$	$5$
$600-700$	$4$
$700-800$	$3$

The mean deviation about the mean for the following data is

Class Interval	$0-4$	$4-8$	$8-12$	$12-16$
Frequency	$4$	$3$	$2$	$1$