After your math teacher quizzes you about the mean (average) and median, the next question she asks will be, “What is the mode?” Let’s take a few moments to find out:

**What is the Mode?**

In a series of numbers, the mode is the value that appears most frequently. [Source: Wikipedia, “Mode”]. Here is a sample set of data: 1, 2, 2, 2, 2, 2, 3, 4, 5, 6, 7, 8, 1256. What is the mode? It is the number 2, which appears more than any other value in the data set.

Note, however, that the mode is not necessarily the same as the mean (or average). In our sample data set, the mean is 100, while the mode is only 2.

Nor is the mode the same as the median (or center value). In our sample data set, the median is 3, while the mode is 2.

**What is the Mode When Two Values Are Equally Common in a Data Set?**

It is possible to have two modes (i.e., two numbers that are most common in a data set). [Source: Douglas, page 12]. Here is an example set of numbers where this result occurs: 9, 10, 10, 10, 11, 12, 13, 13, 13, 14, 14. The two modes are 10 and 13.

As you might have guessed, it is also possible to have three modes, or four, or however many numbers tie for the position of most common value in the set.

**What is the Purpose of the Mode?**

Sometimes the best way to understand a set of numbers is by determining which value appears most frequently (i.e., which number is the mode).

Say, for example, that you are running a hot dog stand, and you need to decide how many condiments to provide for your customers. You could take a survey of customers and ask them how many condiments they like to have available. Some customers will not want any condiments, while a few serious hot dog enthusiasts might want a dozen condiments. You will probably want to know the most frequent amount of condiments listed by the customers. If a high number favor five condiments, then that is probably a safe bet for your business.

When trying to understand data, though, it is often helpful to know the mean and median of a data sample, in addition to the mode, and to plot the data in a histogram or other type of graph.

**Sources**

Douglas, Ph.D. Downing, and Jeffrey Clark Ph.D.. Business Statistics (Barron’s Business Review Series). Hauppauge NY: Barron’s Educational Series, 2003.

“Mode (statistics) – Wikipedia, the free encyclopedia.” Wikipedia, the free encyclopedia. 25 June 2009 .