Question

if a class width is 9 and lower limit of first class interval is 30 then find the upper limit of third class interval​

Answer 1

19.5

10−19,20−29,30−39,...

Here the class intervals are not continuous. To make them continuous take the mean of upper limit of first class and lower limit of second class.

Mean =

2

19+20

=19.5, which gives the upper limit of first class and lower limit of second class for the continuous class intervals.