Although, the question was a bit popular with the candidates, very few of them performed very well in it. Most candidates failed to score good marks in this question because they could not realize that the figures in the table were based on hundreds therefore, they could not work out the figures as required. On the whole, the general candidates’ performance in the question was below average.
In order to score good marks is the question; candidates were expected to present heir answers as follows..
(a)(i) 30 + 20 + 50 + 40 + 60 + 40 + 40 +50 + 20 + 60 + 80 + 40
20 + 20 + 70 + 40 + 70 + 30 + 40 + 80
20
= 900
20 = 45
Mean Income = $4, 500
(ii) Modal Income = $4, 000
(iii) Median Income = 20,20,20,20,30,30,40,40,40,40,
40,40,50,50,60,60,70,70,80,80
Using middle values = 40 + 40 = 80
2 2
Median Income = $4, 000.
(b) Range = $8,000 - $2,000 = $6,000
(c) (i) $90, 000 X 7 = $6, 300
100
(c) (i) Early or late marriages. Early marriages increase birth rates while late
marriages reduce it.
(ii) The higher the number of females in a population, the higher the birth rate
and vice versa.
(iii) Population control methods and campaigns can also reduce birth rates.
(iv) Improved medical facilities increase birth rates, etc.