Arrange numerical data in order from least to greatest. Use the heights of students as a data set example.
Count the number of items in your data set.
Determine whether your data is discrete or continuous. Discrete data can be counted and has a finite number of values in a given range. Continuous data, such as measurements, cannot be counted and has an infinite number of values in a given range.
Define class intervals if you have continuous data values, and skip this step if you have discrete values. Make the class intervals of equal and appropriate size relative to the overall range of your data set. For example, define the class intervals of students' heights to be every 4 inches.
Construct a table with four columns. Label the first cell in the first column "Class Intervals" if you have continuous data, and label the first cell "Class Values" if you have discrete data.
Label the first cell in second column "Tally," the first cell in third column "Frequency" and the first cell in the fourth column "Frequency Percent."
List the class intervals or class values in increasing or decreasing order, depending on your preference, down the first column.
Count the number of times each piece of data falls within a specific class interval or class value. For example, count the number of times students' height falls within each 4-inch interval. Record that information in the form of tally marks in the second column, which is labeled "Tally."
Count the tally marks, and record the number in the third column, which is labeled "Frequency." Divide the number in the third column by the total number of data in the entire data set to determine each frequency value.
Multiply each frequency value by 100 to find its frequency percent. Record each frequency percent in the fourth column, which is labeled "Frequency Percent."
Review your counting and calculations for errors.