Mathematics
The histogram below represents the scores obtained by 25 students in a Mathematics mental test. Use the data to :
(i) Frame a frequency distribution table.
(ii) To calculate mean.
(iii) To determine the modal class.
Measures of Central Tendency
Answer
(i) Frequency distribution table :
| Marks (Class) | No. of students (frequency) |
|---|---|
| 0 - 10 | 2 |
| 10 - 20 | 5 |
| 20 - 30 | 8 |
| 30 - 40 | 4 |
| 40 - 50 | 6 |
(ii) Mean
| Marks (Class) | No. of students (frequency) | Class mean (x) | fx |
|---|---|---|---|
| 0 - 10 | 2 | 5 | 10 |
| 10 - 20 | 5 | 15 | 75 |
| 20 - 30 | 8 | 25 | 200 |
| 30 - 40 | 4 | 35 | 140 |
| 40 - 50 | 6 | 45 | 270 |
| Total | Σf = 25 | Σfx = 695 |
By formula,
Mean =
= = 27.8
Hence, mean = 27.8
(iii) From table,
Class 20 - 30 has the highest frequency.
Hence, modal class = 20 - 30.
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