we have
minimum value=56
maximum value=74
i will assume a interval of
1) 56-60 ----> Tally ----> 56,59,60,58----> frequency----> 4
2) 61-65 ----> Tally ---> 63,62,63 ----> frequency ----> 3
3) 66-70 ----> Tally ---> 67,70,69,66,67,70,66,67,68,67----> frequency----> 10
4) 71-75-----> Tally ----> 74,72,72-----> frequency-----> 3