Statistics Definitions > What is a Dot Plot
Dot Plot: Definition
A Dot Plot, also called a dot chart, is a type of simple histogram-like chart used in statistics for relatively small data sets where values fall into a number of discrete bins (categories). A dot plot is similar to a bar graph because the height of each “bar” of dots is equal to the number of items in a particular category. To draw a dot plot, count the number of data points falling in each bin (What is a BIN in statistics?) and draw a stack of dots that number high for each bin.
A dot plot is a graphical display of data using dots. A good example would be the choice of foods that you and your friends ate for snacks. The illustration below shows a plot for a random sample of integers.
In a table chart it looks like this:
In a Dot Plot, it looks like this:
To analyze this chart, the idea is that there are four of you eating snacks together. The choices for the snacks are: pizza, burger, fries and pasta. With the Dot Plot, it indicates that all of you have chosen pizza. In addition, three others in your group added a burger to their snack plate. This chart goes on to identify that two people in your group have added fries, and one in your group has added pasta to his or her meal.
In summary, a Dot Plot is a graph for displaying the distribution of numerical variables where each dot represents a value. For whole numbers, if a value occurs more than once, the dots are placed one above the other so that the height of the column of dots represents the frequency for that value.
If you prefer an online interactive environment to learn R and statistics, this free R Tutorial by Datacamp is a great way to get started. If you're are somewhat comfortable with R and are interested in going deeper into Statistics, try this Statistics with R track.Comments are now closed for this post. Need help or want to post a correction? Please post a comment on our Facebook page and I'll do my best to help!