Question

if the mid values of the class intervalsa are 12,18,24,30,36,then find the class interval with 18 as mid value.

Answer 1

class size=difference between any 2 consecutive mid values
                 =18-12
                 =6

∴class intervals with mid value 18=(18-6/2) to (18+6/2)
                                                         =15 to 21

i hope this helps!!

Answer 2

Given:
Mid values of Class Interval are 12,18,24,30,36

To Find:
Class Interval with 18 as mid value.

solution:

size of Class Interval = Difference between the midvalues of any two consecutive classes= 18-12=6

The class boundaries for different class interval is obtained by adding half of the magnitude of class interval for upper class interval and subtracting half of the magnitude for lower class interval.

So class interval with 18 as mid value:
upper class interval = 18+ 6/2=18+3=21

lower class interval= 18-6/2=18-3=15

Therefore class interval with midvalues 18 is 15-21