ICSE Class X Math 2014 Solved Paper
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Question : 34
Total: 52
Calculate the mean of the distribution given below using the short cut method.
| Marks | No. of students |
|---|---|
| 11-20 | 2 |
| 21-30 | 6 |
| 31-40 | 10 |
| 41-50 | 12 |
| 51-60 | 9 |
| 61-70 | 7 |
| 71-80 | 4 |
Solution:
| Marks(C.I.) | No. of students (f) | MeanValue(x) | | |
|---|---|---|---|---|
| 11-20 | 2 | 15.5 | -30 | -60 |
| 21-30 | 6 | 25.5 | -20 | -120 |
| 31-40 | 10 | 35.5 | -10 | -100 |
| 41-50 | 12 | 45.5 | 0 | 0 |
| 51-60 | 9 | 55.5 | 10 | 90 |
| 61-70 | 7 | 65.5 | 20 | 140 |
| 71-80 | 4 | 75.5 | 30 | 120 |
| Σf=50 | Σfd=70 |
Assumed mean
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