The mode of the observations $4, 5, 6, 3, 4, 3, 3, 2, 3, 5$ is $\ldots \ldots \ldots \ldots .$

If $\bar{x} = Z - 3$ and $M = 22$,then the mean is ..........

$\sum_{i=1}^{10} (x_i - \bar{x}) = \dots$

For a given frequency distribution,assumed mean $A = 25$,$\Sigma f_{i} d_{i} = 120$ and $\Sigma f_{i} = 140$. Then,the mean $\bar{x} = \dots$

Find the unknown entries $a, b, c, d, e, f$ in the following distribution of heights of students in a class:

Height (in $cm$)	Frequency	Cumulative frequency
$150-155$	$12$	$a$
$155-160$	$b$	$25$
$160-165$	$10$	$c$
$165-170$	$d$	$43$
$170-175$	$e$	$48$
$175-180$	$2$	$f$
Total	$50$	-

Find the mean of the following frequency distribution:

Class	$21-25$	$26-30$	$31-35$	$36-40$	$41-45$	$46-50$	$51-55$
Frequency	$18$	$32$	$30$	$40$	$25$	$15$	$40$

(in $.675$)