search for: fitterma

I fit my CDF to sum of exponentials and now I want to take the numerical derivative of this function to obtain probability density.I will really appreciate your help reagrding the error messages I am getting which I don't understand. * * > fitterma <- function(xtime) { a <- -0.09144115 b <- -0.01335756 c <- -2.368057 d <- -0.00600052 return(exp(a+b*xtime)+exp(c+d*xtime)) } > numericDeriv(fitterma,"xtime") *Error in numericDeriv(fitterma, "xtime") : * * cannot coerce type 'closure' to v...

Hello All: I have defined the following function (fitterma as a sum of exponentials) that best fits my cumulative distribution. I am also attaching the "xtime" values that I have. I want to try two things as indicated below and am experiencing problems. Any help will be greatly appreciated. Best, Parmee ----------------------- *fitterma <...