In the proliferated cell ploidy testing, I encountered a bimodality phenomino
There are a number of existing tests for the modality of a density underlying an observed distribution, including Silverman’s test, the Dip test, the Excess Mass test, and the MAP and RUNT tests.
As a simple illustration, consider a system described by a random variable X, which switches between two well defined states, 1 and 2 with probabilities p and 1-p. Assume that the conditional density of X given the state is normal in each of states 1 and 2 and denote it f1(x) and f2(x), respectively. Then the unconditional density will be p f1(x) + (1-p) f2(x). It can be easily observed that if the means of the two densities are different, then certain combinations of the standard deviations and the probability p result in a bimodal unconditional density.
