# Compare tests with last-observation-caried forward
#________________________________________________________Create dataset
createdata <- function(n0, m0, sd0, n1, m1, sd1) {
DV <- rnorm(n0, mean=m0, sd=sd0)
IV <- rnorm(n1, mean=m1, sd=sd1)
tmpdata <- data.frame( cbind(DV, IV) )
return(tmpdata)}
#________________________________________________________Carry data
# set nr-records (last measurement carried forward)
carrydata <- function(dataset, nrec) {
tmpdata <- dataset
i <- 1
while(i <= nrec ) {
tmpdata[i,2] <- tmpdata[i,1]
i <- i+1 }
return(tmpdata)
}
#________________________________________________________t-tests n-times
#________________________________________________________Last carried forward
testn <- 1000
datapvalue<- vector(length=testn)
i <- 1
while(i <= testn ) {
#Ho is false
x <- createdata(26, 30.45, 9.61, 26, 35.81, 8.88)
#Ho is true
#x <- createdata(26, 30.45, 9.61, 26, 30.45, 9.61)
#Last measure carried forward
z <- carrydata(createdata(13, 30.45, 9.61, 13, 30.45, 9.61), 18)
#Sampled
#z <- createdata(13, 30.45, 9.61, 13, 30.45, 9.61)
Newdata <- rbind(x,z)
result <- t.test(Newdata$DV, Newdata$IV,paired=TRUE)
datapvalue[i] <- result$p.value
i <- i+1 }
#________________________________________________________all data
testn <- 1000
datapvalue<- vector(length=testn)
i <- 1
while(i <= testn ) {
#Ho is false
Newdata <- createdata(39, 30.45, 9.61, 39, 35.81, 8.88)
#Ho is true
#Newdata <- createdata(39, 30.45, 9.61, 39, 30.45, 9.61)
result <- t.test(Newdata$DV, Newdata$IV,paired=TRUE)
datapvalue[i] <- result$p.value
i <- i+1 }
#________________________________________________________print testvalues
test <- data.frame(datapvalue)
names(test ) <- "p"
# > .05 en < .01
i <- 1
while(i <= testn ) {
test$cat <- ifelse(test$p > 0.05, 0,
ifelse( test$p < 0.01, 2, 1) )
i <- i+1 }
slices <- table( test$cat )
lbls <- c("NS", "<.05", "<.01")
pct <- round(slices/sum(slices)*100)
lbls <- paste(lbls, pct) # add percents to labels
lbls <- paste(lbls,"%",sep="") # ad % to labels
pie(slices,labels = lbls, col=rainbow(length(lbls)), main="Pie Chart of P-values")
