A class interval of data has 15 as the lower limit and 25 as the size . Then the class mark is `"_______"`.

For class interval 20-25 write the lower class limit and the upper class limit.

In the class interval 20 - 30, the lower class limit is _______

For class interval 35-45 write the lower class limit and the upper class limit.

The mid-value of a class interval is 25 and the class size is 8. The class interval is

The class marks of a class is 25 , and if the upper limit of that class is 40 , then its lower limit is "_______"

If the upper and the lower limits of a class interval are 16 and 10, the class-interval is ...

From the following frequency table. Find : (a) The frequency of fifth class interval (b) The upper class limit of third class interval. (c) The lower class limit of second class interval. (d) The class mark of sixth class interval.