Normal Quantile Plot

Use the Normal Quantile Plot option to visualize the extent to which the variable is normally distributed. If a variable is normally distributed, the normal quantile plot approximates a diagonal straight line. This type of plot is also called a quantile-quantile plot, or Q-Q plot.

The normal quantile plot also shows Lilliefors confidence bounds (Conover 1980) and probability and normal quantile scales.

Figure 3.7 Normal Quantile Plot 

Note the following information:

• The vertical axis shows the column values.

• The upper horizontal axis shows the normal quantile scale.

• The lower horizontal axis shows the empirical cumulative probability for each value.

• The dashed red line shows the Lilliefors confidence bounds.

For statistical details, see Normal Quantile Plot.