The mean deviation from the mean for the data $ 3, 10, 10, 4, 7, 10, 5 $ is:

If the mean deviation of the data $1, 1+d, 1+2d, \ldots, 1+100d$ $(d > 0)$ from their mean is $255$,then $d$ is equal to:

If $\bar{x}$ is the mean of $n$ observations $x_1, x_2, \ldots, x_n$,then the mean of the absolute deviations of these observations from $\bar{x}$ is

The mean deviation about the mean for the data:

$x_i$	$5$	$7$	$9$	$10$	$12$	$15$
$f_i$	$8$	$6$	$2$	$2$	$2$	$6$

is equal to: (in /$13$)

The frequency distribution of the age of students in a class of $40$ students is given below.

Age	$15$	$16$	$17$	$18$	$19$	$20$
No. of students	$5$	$8$	$5$	$12$	$X$	$Y$

If the mean deviation about the median is $1.25$,then $4X + 5Y$ is equal to:

If the mean deviation of $5$ observations about the mean $3$ is $1.2$,find the coefficient of mean deviation.