PCB: PCB concentrations in Lake Cayuga fish

In NRAIA: Data sets from "Nonlinear Regression Analysis and Its Applications"

Description

The PCB data frame has 28 rows and 2 columns giving the concentration of polychlorinated biphenyls (PCB's) in fish caught in Lake Cayuga in northern New York state. The fish had been tagged as yearlings so their ages could be accurately determined.

Format

This data frame contains the following columns:

age

a numeric vector giving the age of the fish in years.

conc

a numeric vector giving the concentration of PCB's in the fish.

Source

Bates and Watts (1998), Nonlinear Regression Analysis and Its Applications, Wiley (Appendix A1.1).

Examples

str(PCB)
# compare to Figure 1.1 (p. xxx)
xyplot(conc ~ age, PCB, aspect = 'xy',
     type = c("g", "p"), xlab = "Age of fish (yr)",
     ylab = "PCB concentration")
# compare to Figure 1.2 (p. xxx)
xyplot(conc ~ age, PCB, scales = list(y = list(log = 2)),
     aspect = 'xy', type = c("g", "p", "smooth"),
     xlab = "Age of fish (yr)",
     ylab = "PCB concentration")
# linear model in cube root of age
summary(fm1 <- lm(log(conc) ~ I(age^(1/3)), data = PCB))
xyplot(log(conc) ~ I(age^(1/3)), data = PCB, aspect = 'xy',
     xlab = "Cube root of age (yr)", type = c("g", "p", "r"),
     ylab = "log(PCB concentration)",
     main = "Transformed PCB data and fitted line",
     sub = deparse(fm1$call$formula))
# diagnostic plots
opar <- par(mfrow = c(2, 2))
plot(fm1, which = 1:4, las = 1)
par(opar)

NRAIA documentation built on May 2, 2019, 4:52 p.m.