Question
Calculate the mean of the following frequency distribution, using the step-deviation method :
| Class | 0 - 50 | 50 - 100 | 100 - 150 | 150 - 200 | 200 - 250 | 250 - 300 |
| Frequency | 17 | 35 | 43 | 40 | 21 | 24 |
