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प्रश्न
Find the mean of the following frequency distribution by the short cut method :
| Class | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 |
| Frequency | 9 | 12 | 15 | 10 | 14 |
उत्तर
| Class Interval | xi | fi | A = 25 d = x - A |
`f_i d` |
| 0-10 | 5 | 9 | -20 | -180 |
| 10-20 | 15 | 12 | -10 | -120 |
| 20-30 | A = 25 | 15 | 0 | 0 |
| 30-40 | 35 | 10 | 10 | 100 |
| 40-50 | 45 | 14 | 20 | 280 |
| Total | 60 | 80 |
`barx = A + (Σf_i d)/(Σf_i)`
`barx = 25 + 80/60`
`barx = 25 + 1.33`
`barx = 26.33`
`therefore` Mean = 26.33
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The distribution given below shows the marks obtained by 25 students in an aptitude test. Find the mean, median and mode of the distribution.
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