Grouped Frequency Distribution

A grouped frequency distribution is a way to organize data into intervals or classes and record the number of observations that fall into each interval. It is used when dealing with a large set of data and provides a concise representation of the data distribution.

Class Intervals

In a grouped frequency distribution, the data is divided into intervals or classes. Each class represents a range of values. For example, in the given frequency distribution, the class intervals are 1-20, 21-40, 41-60, and so on.

Class Width

The class width refers to the size or width of each class interval. It is calculated by subtracting the lower limit of one class from the lower limit of the next class. In this case, the lower limits of the class intervals are 1, 21, 41, and so on.

To find the class width, we subtract the lower limit of one class from the lower limit of the next class:

Class width = 21 - 1 = 20

Therefore, the class width in this grouped frequency distribution is 20.

Answer Explanation

The correct answer is option 'D' (20). The class width is calculated by subtracting the lower limit of one class from the lower limit of the next class. In this case, the lower limits of the class intervals are 1, 21, 41, and so on. By subtracting the lower limit of one class (1) from the lower limit of the next class (21), we get a class width of 20.

It is important to note that the class width remains constant throughout the grouped frequency distribution. This allows for a consistent representation of the data and facilitates comparisons between different classes. The class width also determines the number of intervals required to cover the entire range of data.

By knowing the class width, one can easily calculate the upper limits of the class intervals by adding the class width to the lower limit. This helps in organizing the data and constructing the frequency distribution table.

In conclusion, the class width in the given grouped frequency distribution is 20 (option 'D').