JAMB Economics 2018 Paper

Concept:The median is the middle value in an ordered data set.When the total frequency is even, the median is the average of the two middle values.Explanation:Total frequency: $N = 2 + 1 + 4 + 3 + 3 + 1 + 6 = 20$.Since $N = 20$ is even, the median lies between the $10$th and $11$th items.Compute the cumulative frequencies:$8: 2$$10: 3$$12: 7$$16: 10$$18: 13$$20: 14$$24: 20$The $10$th item is $16$, because the cumulative frequency reaches $10$ at $X = 16$.The $11$th item is $18$, because the cumulative frequency reaches $13$ at $X = 18$.Median $= \dfrac{10\text{th value} + 11\text{th value}}{2} = \dfrac{16 + 18}{2} = 17$.Answer:B. $17.0$