Size of item | 1-4 | 4-9 | 9-16 | 16-27 |
Frequency | 6 | 12 | 26 | 20 |
size |
x |
f |
xf |
1-4 |
2.5 |
6 |
15 |
4-9 |
6.5 |
12 |
78 |
9-16 |
12.5 |
26 |
325 |
16-27 |
21.5 |
20 |
430 |