- Hi every body, i am using D_f_norm function from library stat in R i am using it to find the standard deviation of the output of a function 'calculate_Z0' that has one of it is inputs as a random variable 'W' , with a standard deviation 'Sigm3LER', when i change the mean of this random variable 'Width', i expected the standard deviation output from d_f_norm to change respectively. here is the code i use Z0_extra <- function(W, Thickness,Height,Spacing) { f <- function(vec) { calculate_Z0(vec[1],Thickness, Height,Spacing) } tmp <- D_f_norm(f, means=c(Width), sds=c(Sigm3LER)) list(mean=tmp$mean ,sd=tmp$sd ) } calculate_Z0 <- function(W,Thickness, Height, Spacing) { Z0 <- sqrt((Resistivity/(Thickness * W))/(2*3.14*5*10^9*(epsilon*(1.15*(W/Height) + 2.8* (Thickness/Height)^0.222 + 2*( 0.03*(W/Height)+0.83*(Thickness/Height)-.07*(Thickness/Height)^0.222)*(Spacing/Height)^ (-1.34)) ))) } but this does not happen, although i change the mean of the output "Width", the standard deviation of the output function 'Z0_extra' does not change. i do not no if this the correct output and i have to change my expectations or there is something wrong in the way i use D_f_norm. can any one advise me on that? thanks and best regards Eman [[alternative HTML version deleted]]