Description Usage Format Details Source Examples
The logist.data
data frame has 1100 rows and 3 columns of records of
the simulated masses for whiskered tern chicks between 0 and 21
days of age.
1 |
This object of class c("nfnGroupedData", "nfGroupedData",
"groupedData", "data.frame")
containing the following columns:
a numeric vector of chick masses (g).
a numeric vector of chick ages (days).
an ordered factor indicating unique id of each simulated individual, i.e. which data belongs to which individual.
No published parameter estimates with associated variability are available for
positive-negative growth curves. These data were simulated using
an 3-parameter positive-negative Richards curve (SSposnegRichards
(model 20)), using parameters drawn from normal distributions with the following
means (standard deviations):
1 2 3 | Asym=92.35 (15.65)
K=0.06 (0.138)
Infl=0.294 (1.72)
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These values were taken from Pallisson et al. (2008) for 75 chicks reported.
Each simulated individual had 11 measurements
stratified through the development period, with 1-2 day random differences in timing
of each measurement.
This data object has methods for nlme
grouped-data classes.
Paillisson, J.-M., Latraube, F. & Reeber, S. (2008) Assessing growth and age of Whiskered Tern Chlidonias hybrida chicks using biometrics. Ardea, 96, 271-277.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | require(stats); require(graphics)
#view data
logist.data
#create list for fixed parameters
modpar(logist.data$age, logist.data$mass, force4par = TRUE, pn.options = "myoptions")
plot(mass ~ age, data = logist.data, subset = id == "0.002",
xlab = "Chick age (day)", las = 1,
ylab = "Chick mass (g)",
main = "logist.data and fitted curve (Chick #2 only)")
change.pnparameters(M=1, pn.options = "myoptions") # set curve to logistic (M=1) in subsequent fit
fm1 <- nls(mass ~ SSposnegRichards(age,Asym=Asym,K=K,Infl=Infl,
modno=20, pn.options = "myoptions"),
data = logist.data, subset = id == "0.002")
age <- seq(0, 166, length.out = 101)
lines(age, predict(fm1, list(age = age)))
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