# Lexis ratio

The **Lexis ratio,** also known as *Q*, is a ratio used in statistical analysis to evaluate how data compares to a Bernoulli distribution. It is computed as follows:

Where σ is the variance given from a set of **Lexis trials** and σ_{B} is the variance computed from the expected Bernoulli distribution. Trials where L falls significantly above or below 1 are known as *supernormal* and *subnormal,* respectively.

Subnormal trials are particularly of note because they tend to indicate that the data follows a Poisson distribution.