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Question
Find the mean for the following distribution:
| Class Interval | 20 - 40 | 40 - 60 | 60 - 80 | 80 - 100 |
| Frequency | 4 | 7 | 6 | 3 |
Solution
| Class Interval | f | x | fx |
| 20 - 40 | 4 | 30 | 120 |
| 40 - 60 | 7 | 50 | 350 |
| 60 - 80 | 6 | 70 | 420 |
| 80 - 100 | 3 | 90 | 270 |
| 20 | 1160 |
∑f = 20 and ∑fx = 1160
`barx = (∑ "f"x)/(∑ "f")`
`barx= 1160/20`
`barx` = 58
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