The mode is another measure of center. It is the easiest measure of center to determine. All that you must do is determine which value in a set appears the most.

Check out some examples.

#1)  The following list gives the ages of children at a birthday party. 6 years, 8 years, 9 years, 11 years, 6 years, 5 years, 6 years, 8 years, 10 years, 6 years, 7 years, 8 years, 9 years

The set has 13 data values. In the set 4 of the values are 6 years 3 of the values are 8 years, 2 of the values are 9 years and the rest of the values in the list appear once.

Because 6 years appears more than any other value in the list, in other words it appears the MOST, we can say that the mode is 6 years.

#2)  The following set of data shows the number of times a students has watched his or her favorite movie.

2, 3, 4, 2, 5, 1, 1, 2, 3, 3, 6, 6, 9, 7, 10, 4, 4, 5

From the list we can see that three people replied that they watched the movie three times and three people watched the movie four times. Each of the other numbers appear 2 or less times in the list. Therefore the mode is both 3 and 4.

Please note: There can be more than one mode if both numbers appear the most.

#3)  Angela has recorded the heights of the tomato plants in the classroom.

4 in, 6 in, 3 in, 8 in, 10 in, 2 in, 7 in, 1 in

Notice that all of the numbers appear once. There is no value that appears more than the others. When this happens we say that there is no mode.

Note: When there is no mode, we DO NOT say that the mode is zero. A mode of zero would be that 0 appears the most. In this example, 0 is not even one of the data values! So instead, we say that there is NO MODE.

Let's summarize:

To determine the mode, we select the value in the set that appears the most. If there are two or more numbers that both appeared the most, they are each listed as a mode. If all the numbers appear the same number of times, then we say there is no mode. Only write that there is a mode of zero if zero is the number that appears the most.

Related Links:
Probability and Statistics