The distribution of numbers of open channels in multi-channel patches

Assumptions inherent in use of the binomial distribution are relaxed in order to identify alternative distributions with different variances, for fitting to the frequency distributions of numbers of open channels in multi-channel patches. The variance is less than that for the binomial distribution with the same expectation when either there is a negative interaction between channels or channels have different probabilities of being open. When the variance is greater, this may be because of positive interaction between channels or non-stationary behaviour. Use of the distributions and lack-of-fit statistics is illustrated.