Use the field/slider to specify the maximum number of principal components to compute and plot.Principal components are computed only when there are no With Variables . The number of displayed principal components is determined by either this number or the number corresponding to the Cumulative Proportion of Variation to Explain , whatever is smaller.Tip : To change the scale of the slider, right-click on the slider and select from the pop-up menu. Change the upper and/or lower boundaries in the window that appears, to rescale the slider and click .