6. Three swimmers Alan, Diane and Gopal record the number of lengths of the swimming pool they swim during each practice session over several weeks. The stem and leaf diagram below shows the results for Alan.
| Lengths | 20 means 20 | |
| 2 | 0122 | \(( 4 )\) |
| 2 | 55667789 | \(( 7 )\) |
| 3 | 012224 | \(( 5 )\) |
| 3 | 566679 | \(( 5 )\) |
| 4 | 01333333444 | \(( 10 )\) |
| 4 | 5556667788999 | \(( 12 )\) |
| 5 | 000 | \(( 3 )\) |
- Find the three quartiles for Alan's results.
The table below summarises the results for Diane and Gopal.
| Diane | Gopal |
| Smallest value | 35 | 25 |
| Lower quartile | 37 | 34 |
| Median | 42 | 42 |
| Upper quartile | 53 | 50 |
| Largest value | 65 | 57 |
- Using the same scale and on the same sheet of graph paper draw box plots to represent the data for Alan, Diane and Gopal.
- Compare and contrast the three box plots.