Question

The following is the distribution of weekly wages of workers in a factory. Calculate the arithmetic mean of the distribution.

Weekly Wages (Rs.)	No. of Workers
$240-269$	$7$
$270-299$	$19$
$300-329$	$27$
$330-359$	$15$
$360-389$	$12$
$390-419$	$12$
$420-449$	$8$

• A. $352.3$
• B. $344.5$
• C. $226.7$
• D. $336.7$

Answer 1

The correct option is D $336.7$

Class Intervals	Mid-values (x)	Frequency(f)	fx
$240-269$	$254.5$	$7$	$1,781.5$
$270-299$	$284.5$	$19$	$5,405.5$
$300-329$	$314.5$	$27$	$8,491.5$
$330-359$	$344.5$	$15$	$5,167.5$
$360-389$	$374.5$	$12$	$4,494$
$390-419$	$404.5$	$12$	$4,854$
$420-449$	$434.5$	$8$	$3,476$
		$\sum f=100$	$\sum fx=33,670$

Arithmetic mean $=33,670/100=336.7$.