The marks obtained (out of 10) by students in a short quiz are given in the first two columns. A cumulative-frequency column is also provided.
Marks | 2 | 3 | 4 | 5 | 6 | 7
Frequency | 5 | 8 | 6 | 4 | 3 | 2
Cumulative frequency | 5 | 13 | 19 | 23 | 26 | 28
Determine the range of the marks.