29.9.37 Symmetry Plot

Symmetry-Plot

Data Requirements

Select at least one column to create symmetry plot.

Creating the Graph

Select required data.

From the menu, select Plot > Statistical: Symmetry Plot

Template

Symmetry.OTPU(installed to the Origin program folder).

Notes

Symmetry Plot can be used to determine whether the response data is symmetrically distributed. To create a symmetry plot, Origin will

• sort your data in ascending order;
• calculate the median value of dataset;
• draw a scatter plot with the upper distance of the median on the X axis against the lower distance to the median on the Y axis;
• add a reference line Y=X to represent a perfectly symmetric sample;
• create a histogram plot to show the shape of distribution, with a reference line at median value.

Two result sheets will be created, which contain the plot data and result graph(s):

As you can see in the result graph, the points are lying along the line Y=x and the histogram has an approximately symmetrical peak-shaped curve. Therefore, we can conclude that the response data is symmetric with respect to its median and has a a symmetric distribution.

When you selected multiple response columns as Input, choosing the plot menu will open the plot_symmetry dialog which allows you to specify how to arrange the plots: Seperate Layers in Graph or Seperate Graphs.