Dragonflies

On the pond surface
reflected dragonflies clash.
Mirror symmetry.

Paul Glendinning
Department of Mathematics, University of Manchester, UK

Outliers

Mean outliers bark

like hound dogs for our notice.

It’s just a squirrel.

David Carroll

Many data sets in the real world such as opinion surveys or rainfall amounts contain outliers — a value well outside the “typical grouping”. When using the average, or “mean”, to describe the data, a single outlier has a large effect on the average. When we provide a median value along with the mean it help people better understand the story being told by the data without being distracted by the barking dogs. –David Carroll