Prepare a continuous grouped frequency distribution from the following data

Also, find the size of class intervals.

Explanation

Here, we see that the difference between two mid-points is 15-5 i.e., 10.
It means the width of the class interval is 10.
Let the lower limit of the first class interval be a.
Then, its upper limit =a+10
Now, mid value of the first class interval =5
`rArr "Mid value"=("Lower limit"+"Upper limit")/(2)`
`rArr 5=(a+a+10)/(2) rArr 2a+10=10`
`rArr 2a=0 rArr a=0`
So, the first class interval is 0-10.
Now, we prepare a continous grouped frequency distribution table is given below

Hence, the size of the class interval is 10 i.e., 10-0.