Creating a histogram

In a histogram, you can show the distribution of numerical data. The entire range of the numerical values is divided into equal intervals on the Category axis, and for each interval, it is indicated on the Value axis how many individual data values that fall within it.


Histogram example
The histogram above is based on a bar chart. It shows how sales figures are distributed between the lowest and the highest amount. Usually there are gaps between the bars in a bar chart. In a histogram though, the bars are placed next to each other to better visualize the distribution of the numerical values along the range. Each interval of the range, also known as a bin, makes a category that is represented by a bar, and the height of a bar shows the number of data values in that particular interval.

Line charts can also be set up as histograms. The line chart below is based on the same data as the bar chart above. Each vertex on the line reflects the number of data values within the bin in question.
Line histogram

The number of bins can be increased or decreased by dragging the slider on the axis. The histogram below is based on the same data as the other histograms, but the number of bins has been increased from 10 to 60.
Histogram with many bins
The steps below describe how to create a histogram based on a bar chart. A histogram based on a line chart is created in a similar way.

Procedure

  1. In the toolbar, click Add new visualization, add new visualization button, and then select Bar Chart.
    A suggestion of a bar chart is presented.
  2. On the Category axis, select the numerical data column for which the distribution of the values is of interest.
    If the amount of data is big, the range of values on the axis is automatically divided into bins. If no automatic binning is made, do as follows:
    1. Click the column selector on the axis to open its popover.
      Column selector popover
    2. In the popover, click Settings, 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.
    The bars adjust to show how many values that fall within the specified bins.

Example

The table lists body weights for 150 men and women. The weights range from 50.0 to 110.0 kg.
Table used in histogram example
The histogram below displays the distribution of values across 10 bins. Because the entire range is 60 kg, and it is divided into 10 bins, each binned interval comprises 6 kg. That is, the first bar shows the number of people that weighs between 50 and 56 kg, the second bar the number between 56 and 62 kg, and so on.
Histogram example

If you color by gender, you can examine male and female distribution differences as well.
Histogram example

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