Explanation:
A grouped frequency distribution is a way of organizing and presenting data that consists of a range of values divided into groups or intervals, along with the corresponding frequencies. It is used when the data set is large and contains a wide range of values.

The most common form of diagrammatic representation of a grouped frequency distribution is a histogram. A histogram is a graphical representation of data that uses bars to represent the frequency of values within each interval or group. The height of each bar represents the frequency or count of values within that interval.

Advantages of using a histogram:
- It provides a visual representation of the data, making it easier to understand and interpret.
- It shows the distribution and pattern of the data, such as whether it is symmetrical, skewed, or bimodal.
- It allows for easy comparison between different groups or intervals.
- It can be used to identify outliers or unusual patterns in the data.

Steps to create a histogram:
1. Determine the range of values in the data set and divide it into groups or intervals.
2. Count the number of values that fall within each interval.
3. Draw a horizontal axis to represent the range of values and a vertical axis to represent the frequency or count.
4. Draw rectangles or bars for each interval, with the height of each bar corresponding to the frequency of values within that interval.
5. Label the axes and provide a title for the histogram.

Other forms of diagrammatic representation:
- An ogive is a graph that represents the cumulative frequency distribution. It plots the cumulative frequencies against the upper class boundaries of the intervals. It is useful for determining percentiles and quartiles.
- A frequency polygon is a line graph that represents the frequencies of values within each interval. It is obtained by joining the midpoints of the tops of the bars in a histogram with straight lines.
- None refers to the absence of any diagrammatic representation.

In conclusion, the most common and widely used form of diagrammatic representation for a grouped frequency distribution is a histogram. It provides a clear and visual representation of the data, making it easier to analyze and interpret.