r - 绘制与回归线的偏差

Question

我想用（a = 0 和 b = 1）绘制一条回归线，并添加与此偏差的各个点，同时用名称识别数据点。

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)

只是我的意图的手动草图，我只是标记了一个点，例如。画的线需要纤细。

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

...如果您确实想要垂直而不是垂直偏移，这是一个非常简单的选择：

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)

要使这适用于 a 和 b 的任何值，您将使用：

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