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Creating intervals of numerical data

Numerical data can be grouped into intervals. The intervals are named bins and can be handled as categories in an analysis.

The values in a numerical column may not be important individually. Sometimes bins of values are preferred because they can be displayed as categories in a visualization. When you create bins, the range between the lowest value and the highest value in the numerical data column is divided into a number of intervals.

For example, if your data contains age information about a group of people, you may want to arrange the ages into a smaller number of age groups as illustrated below.
binning slider
You decide how many bins the range should be divided into. When binning the data, a slider appears that can be dragged to the wanted number of bins. The bar chart below is based on the same data as above but adjusted to display more bins.
binning slider with many bins

Prerequisites

A numerical data column is selected on an axis.

Procedure

  1. Click the column selector on the axis to open its popover.
  2. In the popover, click Settings button in column selector, and then select Auto-bin column.

    The range of values on the axis is divided into bins. A slider where you can change the number of bins supplements the column selector.
  3. Specify the number of bins by dragging the slider.

Result

The visualization adjusts to reflect the specified number of bins. The endpoints of the intervals are automatically set to neat values.
Tip: If you double-click the slider handle, you can enter the wanted number of bins in the opened dialog. Then the range between the lowest value and the highest value in the numerical data column will be divided into a number of intervals of the same size.

Example

The table lists body heights and weights for 33 individuals, and each individual's height is represented in the sorted bar chart.

By coloring the bars by weight, and binning the numerical values, it is easy to distinguish individuals in certain weight intervals. In the image below, the range is divided into 4 bins. Individuals that weigh too much for their heights, can be spotted.

For example, the dark bar in the left part of the visualization stands out. This individual seems to weigh too much for his height.

For more examples, see Creating a histogram.