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Question
Find the mean of the following frequency distribution :
| Class | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 |
| Frequency | 4 | 4 | 7 | 10 | 12 | 8 | 5 |
Solution
| Class Interval | Xi | fi | fixi |
| 0-10 | 5 | 4 | 20 |
| 10-20 | 15 | 4 | 60 |
| 20-30 | 25 | 7 | 175 |
| 30-40 | 35 | 10 | 350 |
| 40-50 | 45 | 12 | 540 |
| 50-60 | 55 | 8 | 440 |
| 60-70 | 65 | 5 | 325 |
| Total | 50 | 1910 |
`barx = (Σf_iX_i)/(Σ"f")`
`barx = 1910/50`
`barx = 38.2`
∴ Mean = 38.2
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