| Leaves {NRAIA} | R Documentation |
The Leaves data frame has 15 rows and 2 columns of leaf length
over time.
This data frame contains the following columns:
Bates and Watts (1998), Nonlinear Regression Analysis and Its Applications, Wiley (Appendix A4.5).
Originally from Heyes and Brown (1956) in F.L. Milthorpe (ed), The Growth of Leaves, London: Butterworth.
options(show.signif.stars = FALSE)
## first fit a logistic model
fm1 <- nls(Length ~ SSlogis(Time, Asym, xmid, scal), data = Leaves)
summary(fm1)
plotfit(fm1, xlab = "Time from initial emergence (days)",
ylab = "Leaf length (cm)", main = "Logistic growth model")
## compare with Richards growth model
fm2 <- nls(Length ~ Asym/(1+exp(-(Time - xmid)/scal))^exp(-lpow), Leaves,
c(coef(fm1),c(lpow = 0)))
summary(fm2)
anova(fm1, fm2)
plotfit(fm2, xlab = "Time from initial emergence (days)",
ylab = "Leaf length (cm)", main = "Richards growth model")
pm1 <- profile(fm1)
plot(pm1, aspect = 'xy', layout = c(3,1))
plot(pm1, absVal = FALSE, aspect = 'xy', layout = c(3,1))
pm2 <- profile(fm2, alpha = 0.05)
plot(pm2, aspect = 'xy', layout = c(4,1))
plot(pm2, absVal = FALSE, aspect = 'xy', layout = c(4,1))