r - 显示由理论相关值和前四个滞后的置信限组成的图，以确定声明是否正确

Question

x = c(0.80, 1.23, -0.13, -0.65, 0.53, -0.10, -0.96, 1.63, 2.79, 2.02, -1.03, -0.86, 
      0.58, 0.59, 0.60, -1.77, -0.77, -0.73, -0.43, 2.60, -0.81, -2.81, -2.13, 1.66,
      1.54, -0.15, -0.31, 0.09, 2.47, 0.24, -0.75, 2.09, 0.46, -0.80, -0.50, 2.58,
      0.80, 0.39, 0.82, -0.58, -1.09, -0.29, -1.26, -1.72, 1.54, 1.06, 1.21, 0.15, 
     -0.57, -0.32, -1.44, -1.56)

z = acf(x, lag.max = 4, type = c("covariance"))
z

我陷入了这张图片的第三个问题：

标签： rtime-seriesdata-analysis