What is the relation between the mean and the median of a discrete data set?

If $\alpha, \beta, \gamma$ are the mean deviations about the mean,median,and mode of the data $1, 2, 2, 3, 3, 3, 4, 6$ respectively,then

Let $a_1, a_2, \dots, a_{101}$ be a group of real numbers such that $a_i > a_{i+1}$ for all values of $i$ and the mean square deviation of the group is minimum about the number $a_{51}$. Then the mode of the group will be:

For a normal distribution,which of the following relations holds true?

For a discrete series (where all values are not equal),what is the relationship between Mean Deviation $(M.D.)$,Mean $(Mean)$,and Standard Deviation $(S.D.)$?

The mode of the following frequency distribution is:

Class	$0-5$	$5-10$	$10-15$	$15-20$	$20-25$	$25-30$
Frequency $(f_i)$	$3$	$4$	$7$	$11$	$2$	$5$