BOD2 {NRAIA} | R Documentation |
The BOD2
data frame has 8 rows and 2 columns giving the
biochemical oxygen demand versus time in an evaluation of water
quality.
This data frame contains the following columns:
Bates and Watts (1998), Nonlinear Regression Analysis and Its Applications, Wiley, (Appendix A4.1).
Originally from Marske (1967), M.Sc. Thesis, University of Wisconsin - Madison.
str(BOD2) # simplest form of fitting a first-order model to these data (fm1 <- nls(demand ~ A*(1-exp(-exp(lrc)*Time)), data = BOD2, start = c(A = 2.2, lrc = log(0.25)))) coef(fm1) # using the plinear algorithm (fm2 <- nls(demand ~ (1-exp(-exp(lrc)*Time)), data = BOD2, start = c(lrc = log(0.25)), algorithm = "plinear", trace = TRUE)) # using a self-starting model (fm3 <- nls(demand ~ SSasympOrig(Time, A, lrc), data = BOD2)) plotfit(fm3, xlab = "Time (days)", ylab = "Biochemical Oxygen Demand")