FlexParamCurve (version 1.3)

logist_data: Simulated growth of whiskered terns

Description

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.

Usage

data(logist_data)

source

Paillisson, J.-M., Latraube, F. & Reeber, S. (2008) Assessing growth and age of Whiskered Tern $Chlidonias hybrida$ chicks using biometrics. Ardea, 96, 271-277.

Details

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): Asym=92.35 (15.65) K=0.06 (0.138) Infl=0.294 (1.72) 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.

Examples

require(stats); require(graphics)
data(logist_data)
modpar(logist_data$age, logist_data$mass, force4par = TRUE) #create pnmodelparams for fixed parameters
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) # set curve to logistic (M=1) in subsequent fit
fm1 <- nls(mass ~ SSposnegRichards(age,Asym=Asym,K=K,Infl=Infl,
           modno=20),
           data = logist_data, subset = id == "0.002")
age <- seq(0, 166, length.out = 101)
lines(age, predict(fm1, list(age = age)))