How to define the density (or something else) of B in the sequence, considering the number of B in the sequence and the distance between B

Question

[g744695539]

There are sequences like BAAAAAAAAB, AAAABBAAAA, ABAABBAAAA. How to define the density(or something else) of B in the sequence, considering the number of B in the sequence and the distance between B. Are there any mathematical models that can be used for reference? Thanks

[rpolicastro]

Are you looking to do some sort of statistical test, or do you want some parameter(s) that describe the density?

[i.sudbery]

The distance between B and the number of B is the same thing under a random distribution of Bs. Under random occurance, the distribution of distances between Bs will be described by the geometric distribution, and the number of Bs in any given window will be described by the poisson distribution.