In a continuous frequency distribution table if the mid - point of a class is m and the upper class - boundary is u, then let us find out the lower class - boundary.

In a frequency distribution table, the midpoints of the classes are 15, 20, 25 30, ….. respectively. The class having midpoint as 20 is

In a frequency distribution table, the mid - point of a class is 10 and the class size of each class is 6; the lower limit of the class is

In a continuous frequency distribution table, if the mid - point of a class is 42 and class size is 10, then let us write the upper and lower limit of the class.

Let us write the frequency density of the first class of the above frequency distribution table.