Question

The following table gives the number of boys of a particular age in a class of $40$ students. Calculate the mean age of the students.

Age (in years)	$15$	$16$	$17$	$18$	$19$	$20$
No. of students	$3$	$8$	$10$	$10$	$5$	$4$

Answer 1

Mean age $=\frac{\sum x_i{f}_i}{\sum f_i}$

$\Rightarrow$mean $=\frac{(15\times 3)+(16\times 8)+(17\times 10)+(18\times 10)+(19\times 5)+(20\times 4)}{3+8+10+10+5+4}$

$\Rightarrow$mean age $=\frac{45+128+170+180+95+80}{40}$

$\Rightarrow$mean age $=17.45$