The following table shows the number of children in each house of a society.
Number of Children Number of Houses
0 4
1 10
2 19
3 3
What is the average number of children per house?

To find the average number of children per house, we use the weighted average formula:
Average=
∑f
∑(f×x)
​

where x is the number of children and f is the number of houses (frequency).

Calculate the total number of children (∑(f×x)):

∑(f×x)=(0×4)+(1×10)+(2×19)+(3×3)
∑(f×x)=0+10+38+9=57
Calculate the total number of houses (∑f):

∑f=4+10+19+3=36
Calculate the average:

Average=
36
57
​
=
12
19
​
≈1.5833
Thus, the average number of children per house is approximately 1.58.