The following table gives the number of children of 150 families in a village
No. of children (x): | 0 | 1 | 2 | 3 | 4 | 5 |
No. of families (f): | 10 | 21 | 55 | 42 | 15 | 7 |
Find the average number of children per family.
Let the assumed mean (A) = 2
No. of children (xi) | No. of families (fi) | ui = xi – A = xi - 2 | fiui |
0 | 10 | -2 | -20 |
1 | 21 | -1 | -21 |
2 | 55 | 0 | 0 |
3 | 42 | 1 | 42 |
4 | 15 | 2 | 30 |
5 | 7 | 3 | 21 |
N = 150 | ∑fiui = 52 |
Average number of children per family = A + 
= 2 + 
= 
= 2.35 (approx)
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