The table shows the distribution of monthly income (in thousands of naira) of workers in a factory
| Monthly Income (N’1000) | 135-139 | 140-149 | 150-154 | 155-164 | 165-169 |
| Number of workers | 20 | 42 | 28 | 38 | 22 |
(a) Draw a histogram for the distribution.
(b) Use your graph to estimate the mode of the distribution.
Explanation
| Monthly Income | Number of Workers | Class Boundaries |
|
135-139 |
20 | 134.5 - 139.5 |
|
140-149 |
42 |
139.5 - 149.5 |
|
150-154 |
28 |
149.5 - 154.5 |
|
155-164 |
38 |
154.5 - 164.5 |
|
165-169 |
22 | 164.5 - 169.5 |
(a)
(b) Modal class: This is the class boundary with the highest frequency.
In this case, it is 139.5 and 149.5.
From the histogram, the modal income is 3 +139.5
= 142.5 or N142500 (in thousands of naira)