LPower                  Calculates either the power, sample size, or
                        detectable effect for a longitudinal study with
                        a repeated measures design.
randomEffectsMatrix     Calculates the variance covariance matrix for a
                        multivariate normal vector when there are
                        random effects.
randomSlopesMatrix      Creates the xMatrix and zMatrix, and attrition
                        rates for a two treatment clinical trial
                        analyzed using the random slopes model.
