The Normal Probability Distribution window contains a normal probability curve for the Z variate. If the data are transformed, two graphs will appear, with the distribution for the transformed data to the right of the distribution for the nontransformed data (as below). If the data are not transformed, only the left-hand graph will appear. Transformations are performed in the Data Summary window.
The normal probability curve is the same as a Cumulative Frequency distribution with the y-axis logn transformed. If the data are normally distributed, the curve will describe a straight line. E.G. in the graph below, transforming the data acts to normalize the distribution. In addition to a normal probability graph, you may also choose to view a frequency distribution bar graph or a cumulative frequency distribution.
Type of plot to graph. Choose either Frequency, Cumulative Frequency, or Normal Probability (as displayed above) curves.
You may Print, Copy, Edit, Export, or List graph values for either graph using the menu commands of the main GS+ window, or via a right-click menu.