For a distribution with equal class widths,the median of $100$ observations is $25$. If the median class is $20-30$ and the number of observations less than $20$ is $45$,what is the frequency of the median class?

The mean and variance of the marks obtained by $n$ students in a test are $10$ and $4$ respectively. Later,the marks of one of the students is increased from $8$ to $12$. If the new mean of the marks is $10.2$,then their new variance is equal to:

In a set of $2n$ distinct observations,each of the observations below the median is increased by $5$ and each of the remaining observations is decreased by $3$. Then the mean of the new set of observations

The coefficients of variation of two distributions are $60$ and $70$. The standard deviations are $21$ and $16$ respectively. Find their means.

If the mean and variance of the frequency distribution are $9$ and $15.08$ respectively,then the value of $\alpha^2+\beta^2-\alpha \beta$ is $............$.

$x_i$	$2$	$4$	$6$	$8$	$10$	$12$	$14$	$16$
$f_i$	$4$	$4$	$\alpha$	$15$	$8$	$\beta$	$4$	$5$

The expenditure of a family for a certain month were as follows:
Food - Rs. $560$,Rent - Rs. $420$,Clothes - Rs. $180$,Education - Rs. $160$,Other items - Rs. $120$
$A$ pie graph representing this data would show the expenditure for clothes by a sector whose angle equals......$^o$