A dot plot is a type of plot that displays the distribution of values in a dataset using dots.
The x-axis shows the individual data values and the y-axis shows the frequency of each value.
This tutorial explains how to calculate the mean, median, and mode of a dot plot.
Example: Calculate Mean, Median & Mode of Dot Plot
Suppose we have the following dot plot that shows the distribution of values for a given dataset:
In order to calculate the mean, median, and mode for this dot plot, we must first write out the values for the dataset.
For example, we can see that the value “1” occurs four times, the value “2” occurs three times, the value “3” occurs one time, and so on.
We can write out the following values for this dataset:
Values: 1, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 6, 6, 6, 6, 7, 8, 10
We can now calculate the mean, median, and mode.
Mean
To find the mean of this dataset, we can add up all of the individual values and divide by the total sample size of 18:
Mean = (1+1+1+1+2+2+2+3+4+5+5+6+6+6+6+7+8+10) / 18 = 4.22.
The mean turns out to be 4.22. This is the average value of the dataset.
Median
To find the median of this dataset, we can write out all of the individual values in order and identify the value that lies directly in the middle:
1, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 6, 6, 6, 6, 7, 8, 10
There are two values in the middle: 4 and 5. Thus, the median is the average of these two values, which is 4.5.
Thus, the median is 4.5. This is the value located directly in the middle of the dataset.
Mode
To find the mode of this dataset, we can identify the values that occur most often:
1, 1, 1, 1, 2, 2, 2, 3, 4, 5, 5, 6, 6, 6, 6, 7, 8, 10
This dataset has two modes: 1 and 6. Each of these values occurs four times in the dataset.
Additional Resources
The following tutorials provide additional information on dot plots:
Dot Plot vs. Histogram: What’s the Difference?
How to Find the Center and Spread of a Dot Plot
The following tutorials explain how to create dot plots using different software:
How to Create a Dot Plot in Google Sheets
How to Create a Dot Plot in Excel
How to Create a Dot Plot in R