Question

Calculate the arithmetic mean for the following birthday gifts using direct method.

Children	0-12	12-24	24-36	36-48	48-60
Birthday gifts	3	5	7	9	11

• A. $36.85$
• B. $23.56$
• C. $24.87$
• D. $12.24$

Answer 1

The correct option is A $36.85$

Children	Birthday gifts$(f_i$)	$x_i$	$f_i{x}_i$
0-12	3	6	18
12-24	5	18	90
24-36	7	30	210
36-48	9	42	378
48-60	11	54	594
		$\sum f_i=35$	$\sum f_i{x}_i=1290$

$Mean=\frac{\sum f_i{x}_i}{\sum f_i}=\frac{1290}{35}=36.85$