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Scores Plot

The scores plot shows the scores of two principle components of a calibration plot against each other. This plot helps to identify samples with similar spectral properties. Those samples are located in the same region of the plot and they are close to each other. In some cases a kind of clustering can be observed.

Additionally, this plot shows the overall variation of samples among the two selected principle components. If the samples are widely spread over the full range of the plot, the variation is big. Relationships between samples can be interpreted with a high degree of certainty for such principle components.

If all samples stick to a particular position in the plot, the overall variation is quite small. This indicates similarity between both principle components and the certainty for prediction of a relationship between samples is very low.

A typical 2D factor plot is shown below, the result window shows multiple plots:

The samples are shown as markers. Hovering the mouse pointer in proximity to the marker will show a Tooltip-Help with additional information about the sample.

In case of a PCA calibration the score plot gives a convenient overview of the qualitative results of the calibration. A good result will show all samples assigned to one of the predefined groups ( see Calibration Model Wizard - Step2 ) and the groups itself will be clearly separated.

It is also possible to make changes to the group assignments. Select the samples by left clicking while holding the Ctrl-Key. The selected samples will be displayed with a stronger outline. Right clicking in the plot will show the context menu. Use the commands "Assign to" or "Assign to new group" to change the assignment of the sample. If a change has been made, the button Recalculate will become active to enable the recalculation of the calibration model.

How do I change the group assignment of samples?

  • Select samples in the plot by left clicking while holding the Ctrl-Key.

  • Open the context menu by right clicking and use the commands "Assign to" or "Assign to new group" to change the assignment of samples.

  • Update the calibration model by clicking on the button Recalculate.