繪制與回歸線的偏差

Question

我想用（a = 0和b = 1）繪制回歸線，並添加與此相關的各個點偏差以及用名稱識別數據點。

set.seed(123)
namelab <- paste ("ET", 1:10, sep = "")
xvar <- 1:10
yvar <- rnorm(10, 5, 5)
myd <- data.frame(namelab, xvar, yvar)
plot(xvar, yvar)
abline (a= 0, b = 1, col = "red", lty = 2)

只是我的意圖的手工草圖，我只是標記了一個點，例如。 繪制的線條需要很細。

Answer 1

dev.new(width=4, height=4)
plot(xvar, yvar, asp=1)

a = 0
b = 1

abline (a, b, col = "red", lty = 2)

myd$xint = with(myd, (b*yvar + xvar - b*a) / (b^2 + 1))
myd$yint = with(myd, (b*yvar + b*xvar + a) / (b^2 + 1))

with(myd, segments(xvar, yvar, xint, yint))
with(myd, text(xvar, yvar, labels=namelab, pos=3, cex=0.5))

Answer 2

...如果你確實想要垂直而不是垂直偏移，這里有一個非常簡單的選擇：

set.seed(123)
namelab <- paste ("ET", 1:10, sep = "")
xvar <- 1:10
yvar <- rnorm(10, 5, 5)

plot(xvar, yvar)
abline (a= 0, b = 1, col = "red", lty = 2)
segments(xvar,yvar,xvar,xvar)
text(xvar,yvar,namelab,pos=3)

為了適用於a和b的任何值，您將使用：

segments(xvar,yvar,xvar,((xvar*b)+a))