9709 P52 - Jun 2020 - Q3
2505
Two machines, A and B, produce metal rods of a certain type. The lengths, in metres, of 19 rods produced by machine A and 19 rods produced by machine B are shown in the following back-to-back stem-and-leaf diagram.
Stem-and-leaf diagram:
| A | B | |
|---|---|---|
| 21 | 1 2 4 | |
| 7 6 3 0 | 22 | 2 4 5 5 6 |
| 8 7 4 3 1 1 | 23 | 0 2 6 8 9 9 |
| 5 5 5 3 2 | 24 | 3 3 4 6 |
| 4 3 1 0 | 25 | 6 |
Key: 7 | 22 | 4 means 0.227 m for machine A and 0.224 m for machine B.
- Find the median and the interquartile range for machine A.
- It is given that for machine B the median is 0.232 m, the lower quartile is 0.224 m and the upper quartile is 0.243 m. Draw box-and-whisker plots for A and B.
- Hence make two comparisons between the lengths of the rods produced by machine A and those produced by machine B.
