simDat18: Simulate data for Chapter 18: model selection

In ASMbook: Functions for the Book "Applied Statistical Modeling for Ecologists"

Simulate data for Chapter 18: model selection

Description

Simulate counts of rattlesnakes in Virginia

Usage

simDat18(
  nSites = 100,
  beta1.vec = c(1, 0.2, 0.5, 1, -1),
  ncov2 = 50,
  beta2.vec = rnorm(50, 0, 0),
  show.plot = TRUE
)

Arguments

nSites	Sample size (number of snakes)
beta1.vec	Values of log-linear intercept and coefs of rock, oak, and chip (linear and squared), in this order
ncov2	Number of 'other' covariates
beta2.vec	Values of coefs of the 'other' covariates (all continuous). All at zero by default
show.plot	Switch to turn on or off plotting. Set to 'FALSE' when running sims

Value

A list of simulated data and parameters.

nSites	Sample size
rock	Rock covariate vector
oak	Oak covariate vector
chip1	Chip covariate vector
chip2	Chip^2 covariate vector
Xrest	Array of "other" covariate values
beta1.vec	Parameter values for intercept, rock, oak, chip, chip^2
ncov2	Number of "other" covariates
beta2.vec	Vector of coefficient values for "other" covariates
C	Simulated rattlesnake counts

Author(s)

Marc Kéry

Examples

str(dat <- simDat18())  # With default arguments

#### First variant of data simulation: beta1.vec is identical, beta2.vec is not
# Variant B: execute when you want to play with a small data set
set.seed(18)
trainDat <- simDat18(nSites = 50, beta1.vec = c(1, 0.2, 0.5, 1, -1), ncov2 = 10,
                     beta2.vec = rnorm(10, 0, 0.1), show.plot = TRUE)
testDat <- simDat18(nSites = 50, beta1.vec = c(1, 0.2, 0.5, 1, -1), ncov2 = 10,
                    beta2.vec = rnorm(10, 0, 0.1), show.plot = TRUE)
# Note how relatively different the two realizations of the SAME process are  

#### Second variant of data simulation: both beta1.vec and beta2.vec are identical

# Variant B: execute when you want to play with a small data set
set.seed(18)
beta2.vec <- rnorm(10, 0, 0.1)
trainDat <- simDat18(nSites = 50, beta1.vec = c(2, 0.2, 0.5, 1, -1), ncov2 = 10,
                     beta2.vec = beta2.vec, show.plot = TRUE)
testDat <- simDat18(nSites = 50, beta1.vec = c(2, 0.2, 0.5, 1, -1), ncov2 = 10,
                    beta2.vec = beta2.vec, show.plot = TRUE)
# Note how relatively different the two realizations of the SAME process are

ASMbook documentation built on Sept. 11, 2024, 5:38 p.m.