R/aov.rasch.sim.R

Defines functions aov.rasch.sim

##########################################################################################################
#
# pwrRasch: Statistical Power Simulation for Testing the Rasch Model
#
# Internal function: Computation of Three-Way ANOVA for balanced design
#
# Authors: Takuya Yanagida <[email protected]>
#			     Jan Steinfeld <[email protected]>
#
##########################################################################################################

aov.rasch.sim <- function(data) {
  
  group <- data$group
  person <- data$person
  item <- data$item  
  response <- data$response
  
  a <- length(unique(group))
  b <- length(unique(person))
  c <- length(unique(item))
  
  ###
  
  SS.T <- (1/(a*b/a*c))*sum(response)^2
  
  SS.A <- sum(rowsum(response, group)^2)*(1/(b/a*c))
  
  SS.B <- sum(rowsum(response, person)^2)*(1/c)
  
  SS.C <- sum(rowsum(response, item)^2)*(1/(a*b/a))
  
  ###
  
  SS.interm. <- c(rowsum(response[group == 1], item[group == 1]), rowsum(response[group == 2], item[group == 2]))
  
  SS.BC <- sum(SS.interm.)
  
  SS.AC <- sum(SS.interm.^2)*(1/(b/a))
  
  ###
  
  F.AC <- ((SS.AC - SS.A - SS.C + SS.T)/(c - 1)) / ((SS.BC - SS.B - SS.AC + SS.A)/(a*(b/a - 1)*(c - 1)))
  p.AC <- pf(F.AC, c - 1, a*(b/a - 1)*(c - 1), lower.tail = FALSE)
  
  return(p.AC)
  
}

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pwrRasch documentation built on May 29, 2017, 2:11 p.m.