4 A library has many identical shelves. All the shelves are full and the numbers of books on each shelf in a certain section are summarised by the following stem-and-leaf diagram.
| 3 | 3699 | | | |
| 4 | 67 | | | |
| 5 | 0122 | | | |
| 6 | 00112344444556667889 | | | |
| 7 | 113335667899 | | | |
| 8 | 0245568 | | | |
| 9 | 001244445567788999 | | | |
Key: 3 | 6 represents 36 books
- Find the number of shelves in this section of the library.
- Draw a box-and-whisker plot to represent the data.
In another section all the shelves are full and the numbers of books on each shelf are summarised by the following stem-and-leaf diagram.
| 2 | 12222334566679 | \(( 13 )\) | |
| 3 | 01112334456677788 | \(( 15 )\) | |
| 4 | 223357789 | | |
- There are fewer books in this section than in the previous section. State one other difference between the books in this section and the books in the previous section.