Distinguishing groups in a scatterplot matrix

We described earlier how a scatterplot matrix can help to describe the relationships between 3 or more numerical variables. If each individual belongs to one of several groups, different symbols or colours can be used to distinguish the groups in the scatterplot matrix.

Iris data

The scatterplot matrix below shows measurements of the sepals (length and width) and petals (length and width) of 150 irises that were collected from the Gaspe Peninsula.

From other characteristics of the irises, botanists classified them into three different varieties. Click the checkbox Show Groups to display the different varieties. You should notice that ...

You may select points (with or without the brush) to further investigate this data set.