JAMB Mathematics 2019 Paper

Concept:Mean deviation is the average distance between each data value and the mean of the distribution.It is calculated using the formula:$$MD = \frac{\sum f|x - \overline{x}|}{\sum f}$$Explanation:From the frequency table, first find the total scores and the mean.$$\sum fx = 156, \quad \sum f = 40$$$$\overline{x} = \frac{156}{40} = 3.9$$Next, find the absolute deviation of each score from the mean: $|x - 3.9|$.Then multiply each absolute deviation by its frequency and add the results.$$\sum f|x - \overline{x}| = 60.4$$Now substitute into the mean deviation formula:$$MD = \frac{60.4}{40} = 1.51$$Therefore, the mean deviation of the students' scores is $1.51$.Answer:The correct option is C: $1.51$.