In a frequency distribution,if the mean and median are $21$ and $22$ respectively,then what is the approximate mode?

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.

Find the mode of the given frequency distribution.

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$	$70-80$
$f_i$	$2$	$18$	$30$	$45$	$35$	$20$	$6$	$3$

Find the mode of the following frequency distribution.

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

The sum of the absolute deviations is minimum when taken with respect to:

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 $.....$