Question

The following table shows the monthly income of 20 families.Find the mean monthly income of those families.

Monthly income ($x_i$)	Number of families ($f_i$)	$f_i{x}_i$
20000	2	40000
50000	4	200000
100000	5	500000
75000	6	450000
60000	3	180000

Answer 1

$\sum f_i=2+4+5+6+3=20$
$\sum f_i{x}_i=40000+200000+500000+450000+180000$
$=1370000$
Mean= $\frac{\sum f_i{x}_i}{\sum f_i}=\frac{1370000}{20}$
= Rs. 68500