Find the mean deviation about the mean for the following data: $12, 3, 18, 17, 4, 9, 17, 19, 20, 15, 8, 17, 2, 3, 16, 11, 3, 1, 0, 5$.

The mean deviation from the mean of the discrete data $1, 3, 4, 7, 11, 18, 29, 47, 78$ is

The mean deviation about the median for the observations $70, 42, 63, 34, 44, 54, 55, 46, 38, 48$ is:

Calculate the mean deviation about the mean for the following frequency distribution:

Class interval	$0-4$	$4-8$	$8-12$	$12-16$	$16-20$
Frequency	$4$	$6$	$8$	$5$	$2$

If the mean of the data $p, 6, 6, 7, 8, 11, 15, 16$ is $3$ times $p$,then the mean deviation of the data from its mean is

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: