Question

Find the mean of the following frequency distribution:

Age (in years)	$18$	$19$	$20$	$21$	$22$
No. of boys	$14$	$10$	$20$	$24$	$12$

• A. $19.125$ years
• B. $20.125$ years
• C. $21.125$ years
• D. $21.175$ years

Answer 1

The correct option is B $20.125$ years

Consider the following table to calculate Mean:

$x_i$	$f_i$	$x_i{f}_i$
$18$	$14$	$252$
$19$	$10$	$190$
$20$	$20$	$400$
$21$	$24$	$504$
$22$	$12$	$264$

here,

$\Sigma f_i=80$

$\Sigma f_i{x}_i=1610$

$Mean=\frac{\Sigma f_i{x}_i}{\Sigma f_i}$

$\therefore Mean=\frac{1610}{80}$

$\therefore Mean=20.125$

Hence, option $B$ is correct.