Question 1 Report
The distribution of the masses of a group of persons is shown in the following table
| Mass/kg | 10.5 - 14.4 | 14.5 - 24.4 | 24.5 - 44.4 | 44.5 - 47.4 | 47.5 - 49.4 |
| Number of Persons | 2 | 6 | 18 | 2 | 1 |
Draw a histogram for the distribution
Histogram of Mass Distribution
Since the class intervals are unequal, the vertical axis is frequency density:
\[\text{Frequency density}=\frac{\text{frequency}}{\text{class width}}\]
| Mass (kg) | Class boundaries | Class width | Frequency | Frequency density |
|---|---|---|---|---|
| 10.5–14.4 | 10.45–14.45 | 4 | 2 | 0.50 |
| 14.5–24.4 | 14.45–24.45 | 10 | 6 | 0.60 |
| 24.5–44.4 | 24.45–44.45 | 20 | 18 | 0.90 |
| 44.5–47.4 | 44.45–47.45 | 3 | 2 | 0.67 |
| 47.5–49.4 | 47.45–49.45 | 2 | 1 | 0.50 |
The required histogram is:
For example, the area of the bar from \(24.45\) kg to \(44.45\) kg is \(20\times0.90=18\), equal to its frequency.
Everything you need to excel in your exams