The age of 100 persons present in a workshop is given in the following table. Find the average age of 100 people (by any method):
| Age Group | Number of People |
|---|---|
| 10 – 20 | 8 |
| 20 – 30 | 12 |
| 30 – 40 | 20 |
| 40 – 50 | 22 |
| 50 – 60 | 18 |
| 60 – 70 | 20 |
WBBSE
Class X
Mathematics
Statistics
04 Mark
2025
| Age Group | Number of People (f) | Midpoint (x) | fx |
|---|---|---|---|
| 10 – 20 | 8 | 15 | 120 |
| 20 – 30 | 12 | 25 | 300 |
| 30 – 40 | 20 | 35 | 700 |
| 40 – 50 | 22 | 45 | 990 |
| 50 – 60 | 18 | 55 | 990 |
| 60 – 70 | 20 | 65 | 1300 |
Σ fx = 120 + 300 + 700 + 990 + 990 + 1300
= 4400
Total number of people:
Σ f = 8 + 12 + 20 + 22 + 18 + 20
= 100
\bar{x} = \frac{4400}{100}
\bar{x} = 44
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