Frequency distribution is a way of organizing and presenting data in a tabular format. The data is grouped into classes or intervals, and the number of observations falling into each interval is recorded. The classes of the frequency distribution can be of equal or unequal width. However, it is generally preferable to have classes of equal width.

Reasons why it is preferable to have classes of equal width in the construction of a frequency distribution are:

1. Ease of Calculation: When the classes are of equal width, it becomes easier to calculate the frequency of each class. This is because the width of each class is the same, and the number of observations in each class can be easily determined by counting the number of observations falling within the limits of each class.

2. Better Representation: Equal width classes provide a better representation of the data as compared to unequal width classes. In equal width classes, each observation is assigned to a particular class based on its value. This ensures that all observations are represented in the distribution, and there is no overlap between the classes.

3. Comparability: Equal width classes make it easier to compare different frequency distributions. This is because the classes are standardized, and it becomes easier to compare the frequency of each class across different distributions.

4. Clarity: Equal width classes make the frequency distribution easier to read and understand. This is because the classes are of equal width, and it becomes easier to identify the range of values that are included in each class.

In conclusion, having classes of equal width in the construction of a frequency distribution is generally preferable due to ease of calculation, better representation of data, comparability, and clarity.

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