export (k_hetang,k_ls,k_may,k_ml,preemption.fit,preemption.t,raplot,raplot.paired)
importFrom("stats", "AIC", "coefficients", "lm", "logLik", "pt", "qnorm", "qt", "uniroot", "vcov")
importFrom("graphics", "legend", "par", "points", "plot", "segments")

