Frequency table

A frequency table is a tool used to display data by showing how often specific values or categories appear in a dataset. It provides a clear overview of the data, helps identify patterns, and facilitates comparisons. Frequency tables are commonly used in statistics to quickly assess the distribution of variables within a sample.

A frequency table for the variable 'gender' shows, for example, how often the categories 'male' and 'female' are represented in the sample.

A frequency table typically contains two key pieces of information: absolute frequencies and relative frequencies.

Depending on the subject area and question, the categories or characteristics can be, for example, persons, companies, locations or households.

Frequency tables are often used to get a first overview of the data. The result can then be displayed graphically in a bar chart.

Valid percent

It is particularly important to pay attention to missing or invalid values when creating and interpreting frequency tables. In the field of survey research, missing values are usually found where people have answered with "no answer", "Can't say" or "Don't know". So that the statistics are not distorted by the missing values, you should enter both the percentage and the valid percentage in the frequency table.

How to calculate valid percent?

To calculate valid percent, the absolute frequencies of a characteristic must be divided by the total number of valid cases. If you have asked 30 people in a survey what their favourite car brand is and 7 have said "Don't know", then there are 23 valid cases. If 5 people have answerd Ford, then the valid percentages are 5/23 or 21.7 %

Example for valid percent:

In a Sunday poll asking, "Which party would you vote for if the election were next Sunday?" there might be some undecided respondents. In this case, both the overall percentages and valid percentages are important. The overall percentages, based on all respondents, show support for each party, including the undecided. In contrast, the valid percentages reflect the support among only those who have already made a decision.

Creating a Frequency Table

First, you need a dataset, such as survey data, from which you want to calculate the frequency of a particular variable. For example, let's take the variable "gender" with the categories "male" and "female" in a survey of 10 people.

Sample Dataset:

To calculate the absolute frequency, count how often each category (e.g., "male" and "female") appears in your dataset.

• male: 4 people
• female: 6 people

You calculate the relative frequency by dividing the absolute frequency by the total number of observations and multiplying by 100.

• male: (4/10) * 100 = 40%
• female: (6/10) * 100 = 60%

If your dataset contains missing values (e.g., people who did not answer the question), you only use the valid responses for calculating the valid percentages. The missing values are ignored, so only the valid data is considered. In our example, there are no missing values, so the percentages and valid percentages are the same.

Now you can summarize all the values in a frequency table:

Example with Missing Values:

Suppose one person did not respond to the question about gender, leaving only 9 valid responses. The table would look like this:

In this case, the "Percentage" column is based on all 10 cases (including the missing values), while the "Valid Percentage" only considers the 9 valid responses.

Example frequency table

In the frequency table calculator on DATAtab you can easily create frequency tables for your data. The procedure will now be illustrated with an example:

In a statistics course the participants were asked which brand of car they drive.

That's how it works with DATAtab: Simply copy the table into the descriptive statistics calculator and select the variable Car Brand. Now you can choose which values you want to calculate. The result of the frequency table now looks like this:

Finally, DATAtab also automatically gives you a graphical visualization of the frequency distribution of car brand, here in the form of a bar chart:

If the variable is metrically scaled, a histogram is used to display the frequencies.

Frequency table APA style

If you want to create a frequency table in APA format, you have to take the following into account:

An extension of frequency tables are crosstabs. In crosstabs, not only one but two variables are considered.