3 The times taken, in minutes, by 150 students to complete a puzzle are summarised in the table.
| Time taken | | \(( t\) minutes \()\) |
| \(0 \leqslant t < 20\) | \(20 \leqslant t < 30\) | \(30 \leqslant t < 35\) | \(35 \leqslant t < 40\) | \(40 \leqslant t < 50\) | \(50 \leqslant t < 70\) |
| Frequency | 8 | 23 | 35 | 52 | 20 | 12 |
- Draw a histogram to represent this information.
\includegraphics[max width=\textwidth, alt={}, center]{d1a3524c-a3b5-45fe-86a7-5cbda087efcd-06_1193_1489_886_328} - Calculate an estimate for the mean time for these students to complete the puzzle.
- In which class interval does the lower quartile of the times lie?