Question

In a grouped frequency distribution, the class mark of a class a – 27 is given by 22.5. Find the value of a.​

Answer 1

Class marks are: 15,20,25,...

Lower limit of class 20 is mean of 15 and 20=215+20=17.5

Upper limit of class 20 is the mean of 20 and 25=220+25=22.5

20 is the class mark for the class interval 17.5−22.5