Explanation
5 students got 6 mark each, 4 students got 7 marks each, 7 students got 8 marks each, 10 students got 9 marks each and 4 students got 10 marks each.
(a) Range is the difference of highest mark and lowest mark. Here, the highest mark is 10 and lowest mark is 6.
So, the range of mark [tex]= 10-6 = 4[/tex]
(b) Total number of students in the group [tex]= 5+4+7+10+4= 30[/tex]
(c) Mean is the simple average. So, for finding the Mean, we will divide the total marks obtained by all students by the total number of students.
Total marks obtained by all students
[tex]= (6*5)+(7*4)+(8*7)+(9*10)+(10*4)\\ \\ = 30+28+56+90+40 = 244[/tex]
So, the Mean mark of the group [tex]=\frac{244}{30}=8.13333....[/tex]
