BOD

Authored by pmagunia on February 26, 2017 - 11:28 AM
Attachment Size
dataset-93773.csv 53 bytes
Documentation

Biochemical Oxygen Demand

The BOD data frame has 6 rows and 2 columns giving the
biochemical oxygen demand versus time in an evaluation of water
quality.

Usage

BOD

Format

This data frame contains the following columns:

Time

A numeric vector giving the time of the measurement (days).

demand

A numeric vector giving the biochemical oxygen demand (mg/l).

Source

Bates, D.M. and Watts, D.G. (1988),
Nonlinear Regression Analysis and Its Applications,
Wiley, Appendix A1.4.

Originally from Marske (1967), Biochemical
Oxygen Demand Data Interpretation Using Sum of Squares Surface

M.Sc. Thesis, University of Wisconsin – Madison.

Examples


require(stats)
# simplest form of fitting a first-order model to these data
fm1 <- nls(demand ~ A*(1-exp(-exp(lrc)*Time)), data = BOD,
   start = c(A = 20, lrc = log(.35)))
coef(fm1)
fm1
# using the plinear algorithm
fm2 <- nls(demand ~ (1-exp(-exp(lrc)*Time)), data = BOD,
   start = c(lrc = log(.35)), algorithm = "plinear", trace = TRUE)
# using a self-starting model
fm3 <- nls(demand ~ SSasympOrig(Time, A, lrc), data = BOD)
summary(fm3)