simDat8: Simulate data for Chapter 8: Two-way ANOVA

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

Simulate data for Chapter 8: Two-way ANOVA

Description

Simulate wing length measurements of mourning cloak butterflies with two factors (habitat and population) including their interaction if so wished (simulation under a fixed-effects model)

Usage

simDat8(
  nPops = 5,
  nHab = 3,
  nSample = 12,
  baseline = 40,
  pop.eff = c(-10, -5, 5, 10),
  hab.eff = c(5, 10),
  interaction.eff = c(-2, 3, 0, 4, 4, 0, 3, -2),
  sigma = 3
)

Arguments

nPops	Number of populations
nHab	Number of habitats
nSample	Samples from each population-habitat combination
baseline	Grand mean length
pop.eff	Population effects, should be nPops - 1 values
hab.eff	Habitat effects, should be nHab - 1 values
interaction.eff	Interaction effects, should be (nPops-1)*(nHab-1) values
sigma	Value for the residual standard deviation

Value

A list of simulated data and parameters.

nPops	Number of populations
nSample	Number of samples per population
baseline	Grand mean length
pop.eff	Population effects
hab.eff	Habitat effects
interaction.eff	Interaction effects
sigma	Residual SD
all.eff	All effects
pop	Indicator for population number
hab	Indicator for habitat number
eps	Simulated residuals
wing	Simulated wing lengths

Author(s)

Marc Kéry

Examples

str(dat <- simDat8())      # Implicit default arguments (for the model with interactions)
# Model with main effects only (and very large sample size; to minimize sampling error 
# and clarify structure of main effects in plot)
str(dat <- simDat8(nSample = 1000, interaction.eff = c(0,0,0,0, 0,0,0,0)))
str(dat <- simDat8(nSample = 10000, interaction.eff = rep(0, 8))) # same, even larger sample size

# Revert to one-way ANOVA model with only effects of pop (with much larger sample size)
str(dat <- simDat8(nSample = 10000, pop.eff = c(-10, -5, 5, 10),
    hab.eff = c(0, 0), interaction.eff = rep(0, 8)))  # note no effect of habitat

# Revert to one-way ANOVA model with only effects of hab
str(dat <- simDat8(nSample = 10000, pop.eff = c(0, 0, 0, 0),
    hab.eff = c(5, 10), interaction.eff = rep(0, 8)))  # note no effect of pop

# Revert to "model-of-the-mean"
str(dat <- simDat8(nSample = 10000, pop.eff = c(0, 0, 0, 0), 
    hab.eff = c(0, 0), interaction.eff = rep(0, 8)))  # note no effect of pop nor of h

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