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

$x_i$	$10$	$30$	$50$	$70$	$90$
$f_i$	$4$	$24$	$28$	$16$	$8$

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 from the mean $10$ of the data $6, 7, 11, 12, 13, \alpha, 12, 16$ 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 $m$ and $M$ denote the mean deviations about the mean and about the median respectively of the data $20, 5, 15, 2, 7, 3, 11$,then the mean deviation about the mean of $m$ and $M$ 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	$1$	$3$	$4$	$1$	$2$