1. A method for accommodating correlated parameters in statistical static timing analysis (SSTA), comprising: determining a correlation between at least two parameters; collapsing or transforming the at least two parameters into a new parameter or a new parameter set; performing the SSTA such that the new parameter or the new parameter set is propagated into the SSTA rather than the at least two parameters separately; specifying a root sum of squares (RSS) list for statistical sources of variation that provides a reduction in overall variance, and adding the new parameter or the new parameter set to the RSS list; returning the new parameter or the new parameter set back to the at least two parameters; and projecting slack using the correlation between the at least two parameters and using a processor, wherein the collapsing or transforming the at least two parameters is performed prior to the performing the SSTA; and the returning the new parameter or the new parameter set back to the at least two parameters is performed prior to the projecting the slack.