Frequency tables, pie charts, and bar charts can be used to display the distribution of a single categorical variable. These displays show all possible values of the variable along with either the frequency (count) or relative frequency (percentage).
Relative frequencies are more commonly used because they allow you to compare how often values occur relative to the overall sample size. They are calculated by dividing the number of responses for a specific category by the total number of responses. Pie charts represent relative frequencies by displaying how much of the whole pie each category represents. Frequency tables and bar charts can display either the raw frequencies or relative frequencies.
If you wish to perform an inferential test on the distribution of a single categorical variable, see the chi-squared goodness-of-fit test.
Example:
A researcher asked her class to pick who would win in a battle of superheros. Below is a frequency table and charts of the results:
Out of a total of 128 responses, 41% (or 52/128) of students reported that Batman would win the battle, followed by Iron Man with 27%, Captain America with 19%, and Superman with 13%. A pie chart and bar chart of these results are shown below:
Example 1: Creating a frequency table and pie chart in Excel 2016 on
This video will show how to create a frequency table and pie chart about beliefs about the impact of social media.
Dataset used in video
PDF corresponding to video
Example 2: Creating a frequency tables and bar charts in RStudio
This video will show how to create a frequency table and bar chart to display the number of patients in different age groups (categorized into young adults, adults, and older adults).
Dataset used in video
R script file used in video