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Question
The weekly wages of 120 workers in a factory are shown in the following frequency distribution table. Find the mean of the weekly wages.
|
Weekly wages
(Rupees)
|
0 - 2000 | 2000 - 4000 | 4000 - 6000 | 6000 - 8000 |
| No. of workers | 15 | 35 | 50 | 20 |
Solution
|
Class
(Weekly wages in thousand rupees) |
Class Mark xi |
Frequency (Number of workers) fi |
Class mark × Frequency xifi |
| 0 - 2000 | 1000 | 15 | 15000 |
| 2000 - 4000 | 3000 | 35 | 105000 |
| 4000 - 6000 | 5000 | 50 | 250000 |
| 6000 - 8000 | 7000 | 20 | 140000 |
| `∑f_i = 120` | `∑x_i f_i = 510000` |
Mean = `(∑x_i f_i )/(∑f_i )`
=`510000/120`
= Rs 4250
Hence, the mean of the weekly wages is Rs 4250.
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