### Statistics

goals
Find the Mean Deviation about median for the following data :

 Class 0  - 10 10 - 20 20 - 30 30 - 40 40 - 50 50 - 60 60 - 70 70 - 80 frequency 5 8 7 12 28 20 10 10

Find the mean $S.D$ of $1,2,3,4,5,6$.
Find the median and mode of the following data.
$28$ , $15$ , $40$ , $25$ , $16$ , $28$ , $32$ , $36$ , $42$ , $16$ , $19$ , $23$
What is the mean value of below numbers?
$2,5,6,8,7,5,4,3,5,2,2,$
The sum of squares of deviations for $10$ observations taken from mean $50$ is $250$. Then Co-efficient of variation is