Q-Q plots

Last updated: Nov 26, 2024

Q-Q plots

Q-Q (quantile-quantile) plots compare two probability distributions by plotting their quantiles against each other. A Q–Q plot is used to compare the shapes of distributions, providing a graphical view of how properties such as location, scale, and skewness are similar or different in the two distributions.

Creating a simple Q-Q plot chart

In the Chart Type section, click the Q-Q plot icon.
The canvas updates to display a Q-Q plot chart template.
Select a variable as the X-axis variable.
Click the Save visualization in the project control. Select Create a new asset or Append to existing asset. Provide a Visualization asset name, an optional description, and a chart name.
Click Apply to save the visualization to the project. The new visualization asset is now available on the Assets tab.

Options

X-axis

Lists variables that are available for the chart's X-axis.

Distribution

The drop-down list provides all available distribution methods.

Auto fit distribution: Automatically fits the distribution (the default setting).
Beta: Returns the value from a Beta distribution with specified shape parameters.
Exponential: Returns the value from an exponential distribution.
Gamma: Returns the value from the Gamma distribution, with the specified shape and scale parameters.
Log-normal: Returns the value from a log-normal distribution with specified parameters.
Normal: Returns the value from a normal distribution with specified mean and standard deviation.
Uniform: Returns the value from the uniform distribution between the minimum and maximum.
Student t: Returns the value from Student's t distribution, with specified degrees of freedom.

Plot type

Select either a Q-Q (quantile-quantile) plot or a P-P (percent-percent) plot.

Auto fit

When enabled, data parameters for the selected Distribution are automatically estimated. When not selected, the Shape and Scale distribution values display.

Shape1

Sets the shape1 value for the Beta distribution. This setting is available only when Auto fit is not enabled and Beta is selected as the Distribution.

Shape2

Sets the shape2 value for the Beta distribution. This setting is available only when Auto fit is not enabled and Beta is selected as the Distribution.

Shape

Sets the shape value for the selected distribution. This setting is available only when Auto fit is not enabled and Gamma or Log-normal is selected as the Distribution.

Scale

Sets the scale value for the selected distribution. This setting is available only when Auto fit is not enabled and Exponential, Gamma, or Log-normal is selected as the Distribution.

Mean

Sets the means value for the Normal distribution. This setting is available only when Auto fit is not enabled and Normal is selected as the Distribution.

Std. dev.

Sets the standard deviation value for the Normal distribution. This setting is available only when Normal is selected as the Distribution.

Min

Sets the minimum value for the Uniform distribution. This setting is available only when Auto fit is not enabled and Uniform is selected as the Distribution.

Max

Sets the maximum value for the Uniform distribution. This setting is available only when Auto fit is not enabled and Uniform is selected as the Distribution.

Degrees of freedom(df)

Set the degrees of freedom value for the Student t distribution. This setting is available only when Auto fit is not enabled and Student t is selected as the Distribution.

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