The mean deviation from the mean for the set of observations $-1, 0, 4$ is

What is the coefficient of mean deviation about the median for the observations $40, 62, 54, 90, 68, 76$?

If $\alpha \neq 0$ and the mean deviation of the observations $\{k \alpha\}$ for $k=1, 2, \ldots, 50$ about its median is $50$,then $|\alpha|=$

The mean deviation of the numbers $a, a+d, a+2d, \ldots, a+2nd$ from their mean is equal to

Calculate the mean deviation about the median age for the age distribution of $100$ persons given below:

Age (in years)	$16-20$	$21-25$	$26-30$	$31-35$	$36-40$	$41-45$	$46-50$	$51-55$
Number of persons	$5$	$6$	$12$	$14$	$26$	$12$	$16$	$9$

If the mean of $4, 7, 2, 8, 6$ and $a$ is $7$,then the mean deviation from the median of these observations is