VPC.graph               calculate percentiles of original data using
                        bin-related weight percentiles of simulated
                        data with corresponding confidence interval
asVPC.binW              calculate percentiles of original data using
                        bin-related weight percentiles of simulated
                        data with corresponding confidence interval
asVPC.distanceW         calculate percentiles of original data using
                        distance-related weight percentiles of
                        simulated data with corresponding confidence
                        interval
makeCOVbin              make the bins with equal number of observations
                        or using user-defined breaks
origdata                sample original data
read_Simdata            calculate percentiles of original data using
                        bin-related weight percentiles of simulated
                        data with corresponding confidence interval
simdata                 sample sim data
