Chemotaxis Assays

What is the purpose of the Rayleigh test when analyzing chemotaxis assays?

The Rayleigh test is a statistical test for the uniformity of a circular distribution of points (cell endpoints).

With p < 0.05, the null hypothesis (uniformity) is rejected, indicating a chemotaxis effect. Like all statistical tests, this one strongly depends on the number of analyzed cells.

Moore BR., 1980, A modification of the Rayleigh test for vector data, Biometrika, Volume 67, 175-180