Mathematics
If the mean of the following distribution is 7.5, find the missing frequency f :
| Variate | Frequency |
|---|---|
| 5 | 20 |
| 6 | 17 |
| 7 | f |
| 8 | 10 |
| 9 | 8 |
| 10 | 6 |
| 11 | 7 |
| 12 | 6 |
Measures of Central Tendency
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Answer
We construct the following table:
| Variate (xi) | Frequency (fi) | fixi |
|---|---|---|
| 5 | 20 | 100 |
| 6 | 17 | 102 |
| 7 | f | 7f |
| 8 | 10 | 80 |
| 9 | 8 | 72 |
| 10 | 6 | 60 |
| 11 | 7 | 77 |
| 12 | 6 | 72 |
| Total | 74 + f | 563 + 7f |
Hence, the value of f is 16.
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