# How to Build a Frequency Table

The Frequency Table is a chart used to organize a set of data into categories, where each category’s value represents the number of times a values occurs in a given category. The Frequency Table is the first step in drawing a Frequency Distribution Chart, or what is also known as a Histogram. The resulting Histogram is a visual representation of the data organized by frequency.

The Frequency Table is divided into six columns. The First column is for the Class Boundaries. The Class Boundaries will determine the upper and lower limits of the values that will be counted as members of a given class. The next column is the Midpoint of each class. The Midpoint of a given class is the value that is exactly between the upper and lower limits of the Class Boundaries.

The third column is the Frequency. This is the where the Frequency table gets its name. It is the count of the numbers of times a data value falls between the upper and lower limits of each class. The sum of all the counts for each of the classes must be equal to the total number of values in the data set.

This brings us to the Relative Frequency. This is equal to the value of the Frequency divided by the total number of values in the data set. This means that the Relative Frequency of a given class cannot ever be greater than one. However, the sum of all these values for all the classes must always equal one.

The fifth column is the Cumulative Frequency. This column is a running total of the Frequency. Its value for the first class has the same value as the Frequency of the first class. Its value for the second class is the sum of the Frequencies of the first and second classes. Its value for the third class is the sum of the Frequencies of the first, second and third classes. This continues until we have a value for all the classes. The Cumulative Frequency of the last class must be equal to the total number of values in the data set.

The sixth, and last column, is the Relative Cumulative Frequency. The values in this column are calculated by dividing the values of the Cumulative Frequency for each class by the total number of value in the data set, Similar to what we did for the Relative Frequency. All of the values for the Relative Cumulative Frequency will be less than one, except for the value of the last class, which will always be equal to one.

Together, these six columns are the Frequency Table, and are the basis of charting the Frequency Distribution, or Histogram.