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प्रश्न
The following table gives the number of boys of a particular age in a class of 40 students. Calculate the mean age of the students
| Age (in years) | 15 | 16 | 17 | 18 | 19 | 20 |
| No. of students | 3 | 8 | 10 | 10 | 5 | 4 |
उत्तर
| x | f | fx |
| 15 | 3 | 45 |
| 16 | 8 | 128 |
| 17 | 10 | 170 |
| 18 | 10 | 180 |
| 19 | 5 | 95 |
| 20 | 4 | 80 |
| `sum`f = N = 40 | `sum`fx = 698 |
Mean age `=(sumfx)/N`
`=698/40=17.45` years
∴ Mean age = 17.45 years
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