Mathematics
To find out the concentration of SO2 (in parts per million, i.e., ppm), in the air, the data was collected for 30 localities in a certain city and is presented below :
| Concentration of SO2 (in ppm) | Frequency |
|---|---|
| 0.00 - 0.04 | 4 |
| 0.04 - 0.08 | 9 |
| 0.08 - 0.12 | 9 |
| 0.12 - 0.16 | 2 |
| 0.16 - 0.20 | 4 |
| 0.20 - 0.24 | 2 |
Find the mean concentration of SO2 in the air.
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