# Normal plot

## Description

The Normal plot is a graphical tool to judge the Normality of the distribution of the sample data.

The horizontal axis of the Normal plot shows the observed values, and the vertical axis shows the corresponding expected number of standard deviations from the mean (z-score), based on the ranks of the observed values. When the option Q-Q plot is selected, the horizontal axis shows the z-scores of the observed values, z=(x−mean)/SD

A straight reference line represents the Normal distribution. If the sample data are near a Normal distribution, the data points will be near this straight line.

## Required input

- Select the variable of interest.
- Optionally select a filter to include a subset of cases.

The horizontal axis of the Normal plot shows the observed values, and the vertical axis shows the corresponding expected number of standard deviations from the mean (z-score), based on the ranks of the observed values.

When the option Q-Q plot is selected, the horizontal axis shows the z-scores of the observed values, z=(x-mean)/SD.

## See also

## Link

Go to Normal plot.