3 The time taken, in minutes, to walk to school was recorded for 200 pupils at a certain school. These times are summarised in the following table.
| Time taken | | \(( t\) minutes \()\) |
| \(t \leqslant 15\) | \(t \leqslant 25\) | \(t \leqslant 30\) | \(t \leqslant 40\) | \(t \leqslant 50\) | \(t \leqslant 70\) |
| 18 | 46 | 88 | 140 | 176 | 200 |
- Draw a cumulative frequency graph to illustrate the data.
\includegraphics[max width=\textwidth, alt={}, center]{ad3a6a8a-23fe-415a-b2f4-7c49136ccc6c-04_1217_1509_705_278} - Use your graph to estimate the median and the interquartile range of the data.
\includegraphics[max width=\textwidth, alt={}, center]{ad3a6a8a-23fe-415a-b2f4-7c49136ccc6c-05_2723_35_101_20} - Calculate an estimate for the mean value of the times taken by the 200 pupils to walk to school.