- A sports teacher recorded the number of press-ups done by his students in two minutes. He recorded this information for a Year 7 class and for a Year 11 class.
The back-to-back stem and leaf diagram shows this information.
| Totals | Year 7 class | | Year 11 class | Totals |
| (6) | 876554 | 1 | | |
| (10) | 9776544422 | 2 | 0569 | (4) |
| (7) | 8754330 | 3 | 34588 | (5) |
| (5) | 99722 | 4 | 05679 | (5) |
| (3) | 840 | 5 | 03556677799 | (11) |
| | 6 | 0333348 | (7) |
Key: \(2 | 4 | 0\) means 42 press-ups for a Year 7 student and 40 press-ups for a Year 11 student
- Find the median number of press-ups for each class.
For the Year 11 class, the lower quartile is 38 and the upper quartile is 59
- Find the lower quartile and the upper quartile for the Year 7 class.
- Use the medians and quartiles to describe the skewness of each of the two distributions.
- Give two reasons why the normal distribution should not be used to model the number of press-ups done by the Year 11 class.