What is the relationship between mean,median,and mode for a moderately skewed distribution?

In a series,if $4$ appears $3$ times,$5$ appears $4$ times,$6$ appears $5$ times,$7$ appears $8$ times,$8$ appears $7$ times,and $9$ appears $6$ times,then the mode of the numbers is = .......

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

Find the mode of the following frequency distribution.

Class	$1 - 10$	$11 - 20$	$21 - 30$	$31 - 40$	$41 - 50$
$f_i$	$5$	$7$	$8$	$6$	$4$

Determine which of the following statements is true: $(1)$ The mode can be calculated using a histogram. $(2)$ The median is not independent of the change of scale. $(3)$ Variance is independent of the change of origin and scale.

Consider the following frequency distribution:

Class	$0-6$	$6-12$	$12-18$	$18-24$	$24-30$
Frequency	$a$	$b$	$12$	$9$	$5$

If $\text{mean} = \frac{309}{22}$ and $\text{median} = 14$,then the value of $(a-b)^{2}$ is equal to $.....$