"Modeling Techniques in Predictive Analytics" 中的基本绘图

Question

我正在尝试绘制 x 和 y 对，如下所示。有人可以为我提供绘制 x1、y1 的基本代码吗？我已经尝试了很多东西来包括 plot(x1,y1) 并且它不识别这些变量。

 # The Anscsombe Quartet in R

# demonstration data from
# Anscombe, F. J. 1973, February. Graphs in statistical analysis. 
#  The American Statistician 27: 17â21.

# define the anscombe data frame
anscombe <- data.frame(
   x1 = c(10, 8, 13, 9, 11, 14, 6, 4, 12, 7, 5),
   x2 = c(10, 8, 13, 9, 11, 14, 6, 4, 12, 7, 5),
   x3 = c(10, 8, 13, 9, 11, 14, 6, 4, 12, 7, 5),
   x4 = c(8, 8, 8, 8, 8, 8, 8, 19, 8, 8, 8),
   y1 = c(8.04, 6.95,  7.58, 8.81, 8.33, 9.96, 7.24, 4.26,10.84, 4.82, 5.68),
   y2 = c(9.14, 8.14,  8.74, 8.77, 9.26, 8.1, 6.13, 3.1,  9.13, 7.26, 4.74),
   y3 = c(7.46, 6.77, 12.74, 7.11, 7.81, 8.84, 6.08, 5.39, 8.15, 6.42, 5.73),
   y4 = c(6.58, 5.76,  7.71, 8.84, 8.47, 7.04, 5.25, 12.5, 5.56, 7.91, 6.89))

# show results from four regression analyses
with(anscombe, print(summary(lm(y1 ~ x1))))
with(anscombe, print(summary(lm(y2 ~ x2))))
with(anscombe, print(summary(lm(y3 ~ x3))))
with(anscombe, print(summary(lm(y4 ~ x4))))

# place four plots on one page using standard R graphics
# ensuring that all have the same scales
# for horizontal and vertical axes
pdf(file = "fig_more_anscombe.pdf", width = 8.5, height = 8.5)
par(mfrow=c(2,2),mar=c(3,3,3,1))
with(anscombe, plot(x1, y1, xlim=c(2,20),ylim=c(2,14), 
  pch = 19, col = "darkblue", cex = 2, las = 1)
title("Set I")
with(anscombe,plot(x2, y2, xlim=c(2,20),ylim=c(2,14), 
  pch = 19, col = "darkblue", cex = 2, las = 1))
title("Set II")
with(anscombe,plot(x3, y3, xlim=c(2,20),ylim=c(2,14), 
  pch = 19, col = "darkblue", cex = 2, las = 1))
title("Set III")
with(anscombe,plot(x4, y4, xlim=c(2,20),ylim=c(2,14), 
  pch = 19, col = "darkblue", cex = 2, las = 1))
title("Set IV")
dev.off()

par(mfrow=c(1,1),mar=c(5.1, 4.1, 4.1, 2.1))  # return to plotting defaults

# suggestions for the student
# see if you can develop a quartet of your own 
# or perhaps just a duet... 
# two very different data sets with the same fitted model

Answer 1

如果您只想绘制 x1 和 y1，请尝试：

plot(anscombe$x1,anscombe$y1)

或（来自您的代码）：

with(anscombe, plot(x1, y1, xlim=c(2,20),ylim=c(2,14), 
  pch = 19, col = "darkblue", cex = 2, las = 1)

您上面的代码将它们绘制到一个 pdf 文件中，从以下行开始：

pdf(file = "fig_more_anscombe.pdf", width = 8.5, height = 8.5)

直到您在以下位置终止 pdf 才会结束：

dev.off()

如果你不终止 pdf，你将永远不会在 R 中看到绘图输出。如果你有多次运行代码，请确保运行没有打开任何 pdf 设备宁：

dev.off()

直到你看到：

Error in dev.off() : cannot shut down device 1 (the null device)

Answer 2

请注意，anscombe 数据集随 R 一起提供，无需定义。

下面的代码设置了一个 2x2 的绘图网格，然后计算了 x 和 y 变量的总体范围。然后对于 i = 1、2、3、4，它创建第 i 个公式并使用计算的范围绘制它。 as.roman 用于获取标题的罗马数字部分。然后我们执行线性回归。我们本可以只写 fm <- lm(fo, anscombe) 来计算回归，但如果我们这样做了，print(summary(fm)) 输出将按字面意思显示 fo 作为公式，这不是很好。最后，我们使用 abline 绘制回归线并打印摘要。

试试这个：

par(mfrow = c(2,2))

xrange <- range(anscombe[1:4])
yrange <- range(anscombe[5:8])

for(i in 1:4) {
  fo <- as.formula( sprintf("y%d ~ x%d", i, i) )
  plot(fo, anscombe, xlim = xrange, ylim = yrange, main = paste("Set", as.roman(i)))
  fm <- do.call("lm", list(fo, quote(anscombe)))
  abline(fm)
  print( summary(fm) )
}

par(mfrow = c(1,1))

给出此图（未显示 print(summary(...)) 的输出）：

"Modeling Techniques in Predictive Analytics" 中的基本绘图

Basic Plotting in "Modeling Techniques in Predictive Analytics"

plot

analytics

r