Mathematics
The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.
| Literacy rate (in %) | Number of cities |
|---|---|
| 45 - 55 | 3 |
| 55 - 65 | 10 |
| 65 - 75 | 11 |
| 75 - 85 | 8 |
| 85 - 95 | 3 |
Statistics
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Answer
We will use assumed mean method to find the mean. Here, a is the assumed mean.
By formula,
Class mark =
| Literacy rate (in %) | Number of cities (fi) | Class mark (xi) | di = xi - a | fidi |
|---|---|---|---|---|
| 45 - 55 | 3 | 50 | -20 | -60 |
| 55 - 65 | 10 | 60 | -10 | -100 |
| 65 - 75 | 11 | a = 70 | 0 | 0 |
| 75 - 85 | 8 | 80 | 10 | 80 |
| 85 - 95 | 3 | 90 | 20 | 60 |
| Total | Σfi = 35 | Σfidi = -20 |
By formula,
Mean =
Substituting values we get :
Hence, mean literacy rate = 69.43 %.
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