I have written two blocks of R-code. I believe that they should both do exactly the same thing - except that one uses a for-loop approach and one uses the sapply function. However, they produce slightly different results. Does anyone know what is causing the slight differences here? Interestingly, both methods produce the same value for the first elements of the output vectors.
Method1:
set.seed(967)n <- replicate(1000, 200)ACF2MA <- sapply(n, function(n1) { acf(arima.sim(n1, model=list(ma=c(0.4))), plot=FALSE)$acf[3]})ACF2AR <- sapply(n, function(n1) { acf(arima.sim(n1, model=list(ar=c(0.45))), plot=FALSE)$acf[3]})
Method2:
ACF2AR1 <- 1:1000 for (i in 1:1000) { YMA <- arima.sim(n=200, model=list(ma=c(0.4))) YAR <- arima.sim(n=200, model=list(ar=c(0.45))) ACF2MA1[i] <- acf(YMA, plot=FALSE)$acf[3] ACF2AR1[i] <- acf(YAR, plot=FALSE)$acf[3] }
Many thanks in advance!
I was expecting the exact same results.