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:

The mean deviation from the mean for the data $6, 7, 10, 12, 13, 4, 12, 16$ is

The mean deviation about the mean for the following data is

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

The mean and variance of $10$ observations are $9$ and $34.2$, respectively. If $8$ of these observations are $2, 3, 5, 10, 11, 13, 15, 21$, then the mean deviation about the median of all the $10$ observations is

If the mean deviation about the median of the numbers $k, 2k, 3k, \dots, 1000k$ is $500$, then $k^{2}$ is equal to :

If $M_1$ is the mean deviation from the mean of the discrete data $44, 5, 27, 20, 8, 54, 9, 14, 35$ and $M_2$ is the mean deviation from the median of the same data,then $M_1 - M_2 =$