set.seed(123456) y <- arima.sim(n = 100, list(ar = 0.9), innov=rnorm(100)) op <- par(no.readonly=TRUE) layout(matrix(c(1, 1, 2, 3), 2, 2, byrow=TRUE)) plot.ts(y, ylab='') acf(y, main='Autocorrelations', ylab='', ylim=c(-1, 1), ci.col = "black") pacf(y, main='Partial Autocorrelations', ylab='', ylim=c(-1, 1), ci.col = "black") par(op)