Width and length of iris sepals

Use this example to discuss clusters in a scatterplot. There appear to be two clusters, even though neither marginal distribution separates into distince clusters. The clusters suggest different varieties of iris.

There appear to be two clusters but the irises were actually classified into three varieties when the data were collected. Click Show Groups to display the different varieties.

This is two variables from a 'classic' data set.

The variables in the scatterplot are the width and length of the sepals from iris flowers that were sampled in the Gaspé Peninsula. In the full data set, petal width and length are also present.