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Question
The following frequency distribution table shows the amount of aid given to 50 flood affected families. Find the mean of the amount of aid.
|
Amount of aid
(Thousand rupees)
|
50 - 60 | 60 - 70 | 70 - 80 | 80 - 90 | 90 - 100 |
| No. of families | 7 | 13 | 20 | 6 | 4 |
Solution
|
Class
(Amount of aid in thousand rupees) |
Class Mark xi |
Frequency (Number of families) fi |
Class mark × Frequency xifi |
| 50 - 60 | 55 | 7 | 385 |
| 60 - 70 | 65 | 13 | 845 |
| 70 - 80 | 75 | 20 | 1500 |
| 80 - 90 | 85 | 6 | 510 |
| 90 - 100 | 95 | 4 | 380 |
| `sum f_i ` = 50 | `sum x_i f_i = 3620` |
Mean = `(sum x_i f_i )/(sum f_i)`
`= 3620/50`
= 72.4 thousand rupees
= Rs 72400
Hence, the mean of the amount of aid is Rs 72400.
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