1. A computer implemented method of crosstalk analysis, comprising: using a computer system which comprises at least one processor and is configured for performing a process comprising: identifying a set of nets in a design; determining, for each net of the set in a path in the design, a probability distribution function (pdf) of a crosstalk delay for the each net of the set, wherein the probability distribution function corresponds to one or more aggressors that contribute to the crosstalk delay; generating a combined or composite probability distribution file for the path that combines probability distribution functions from nets along the path; receiving a desired probability level from a user, and determining a statistical crosstalk path delay for the path using the desired probability level according to the combined or composite probability distribution file.