Boxplot maker
Here you will find everything about the boxplot. You can easily make your boxplot online or just read the theory below. Boxplots give a quick and good picture of existing distributions in your data. To make your own boxplot, simply copy your data into the upper table and select the desired variable below.
Create a Boxplot online
To create a boxplot online, simply select the variables you want to create a boxplot from! Depending on the scale level of the selected variables, the right boxplot will be created! For example, if you select a metric and a nominal variable with three levels, a boxplot will be created for the three groups.
Boxplot explanation
What is a boxplot? Boxplots are used in statistics to clearly display the median, mean and dispersion of data in a chart. The data must be at least interval scaled. A box plot is often used to compare and contrast two or more groups. Boxplots are also called box whisker plots.
Interpreting the Boxplot
A boxplot contains a lot of information, therefore the interpretation of the boxplot can be very versatile. The Boxplot consists of three parts, the box, the T-shaped whisker, also called feeler and two lines.
- the Box
- two strokes
- the T-shaped whisker
The box itself indicates the range in which the middle 50% of all data is located. The lower end of the box is therefore the 1st quantile and the upper end the 3rd quantile.
In the box plot, the solid line indicates the median and the dashed line the mean value.
The T-shaped whiskers go up to the last point, which is still 1.5 times the interquartile distance. Points further away are considered outliers. If no point is more than 1.5 times the interquartile distance away, the T-shaped whisker indicates the maximum or minimum value.
Boxplot Whisker
The definition of whiskers is not always uniform, mostly the upper definition is used, that whiskers go to the last point, which is still within 1.5 times the interquartile distance. Boxplots created online on DATAtab also adhere to this definition. Occasionally, the whiskers are simply the minimum and maximum.
Outliers in a Boxplot
To determine outliers in the given data, interquartile spacing is used. This is done in a similar way to whiskers. All points that are further away than 1.5 times the interquartile distance are considered outliers. So in the online created box plots all values above and below the whisker are outliers.