A meteorologist recorded the daily rainfall, in mm, over a period of 50 days.
| Rainfall (r r\,r mm) | Frequency |
|---|---|
| 0<r≤20 < r \leq 20<r≤2 | 12 |
| 2<r≤42 < r \leq 42<r≤4 | 15 |
| 4<r≤64 < r \leq 64<r≤6 | 10 |
| 6<r≤106 < r \leq 106<r≤10 | 8 |
| 10<r≤2010 < r \leq 2010<r≤20 | 5 |
Estimate the mean daily rainfall. Give your answer correct to 1 decimal place.
Explain why your answer to part (a) is an estimate.