The marks scored by 40 students of class IX in mathematics are given below:

81, 56, 68, 79, 85, 13, 29, 68, 54, 73, 47, 35, 72, 64, 95, 44, 50, 77, 64, 35, 79, 52, 45, 54, 70, 83, 62, 64, 72, 92, 84, 76, 63, 43, 54, 38, 73, 68, 52, 54.


Prepare a frequency distribution with class size of 10 marks.


Marks



Tally marks



Frequency



20-30



I



1



30-40



III



4



40-50



IIII



5



50-60



IIII III



7



60-70



IIII III



7



70-80



IIII IIII



8



80-90



IIII



4



90-100



II



2





Total = 40




15