There are several ways to find the mode depending upon the data type and sample size. In statistics, the mode is the most frequently occurring value in a data set. It is a measure of central tendency. To learn more about the mode, read my post, Measures of Central Tendency.
Finding the Mode for Discrete and Categorical Data
When working with discrete and categorical data, the values naturally form groups with easily countable values. For these data types, just count the number of data points with the same value. Learn about discrete vs. continuous data.
The most straightforward way to find the mode is to order your dataset by values and find the one that occurs most often. This method works best for discrete data and relatively small sample sizes. For example, the two datasets below contain Likert scale values and categorical data.
For the ratings, four is the mode because it occurs more frequently than the other ratings. Similarly, cat is the mode of the pet data.
For larger datasets, you can find the mode using a frequency table. Learn about frequency tables and how to make them with Excel.
For example, the frequency table below contains 126 observations. The mode of this data set is “Very Satisfied” because it occurs 59 times, more frequently than all other values.
How to Find the Mode for Continuous Data
When you have numeric data (aka continuous data), you might not have any values that repeat. In that case, no mode exists because no value occurs more frequently than the others. In the height measurements below, no values repeat.
However, you can find the mode by grouping the values into ranges and then finding the range that occurs most frequently. A histogram is a great tool for this process because it graphically displays the frequencies of ranges. Learn more about Histograms.
The modal class is the most common range, corresponding to the highest bar on a histogram. The mode for grouped data is the midpoint of the modal class. Let’s work through an example!
Download the Excel file for the following example of how to find the mode: HeightFrequencyTable.
For the height data, I group the height values into ranges and show the frequencies. It’s just another type of frequency table. The histogram below the table displays the same information graphically.
The modal class is the highest bar in the histogram, which covers the range of 1.45 to 1.51. The mode is the midpoint of that range—1.48.
Unlike other measures of central tendency, you can find multiple modes when multiple values occur with the same frequency. To learn more, read my post about Bimodal Distributions.