在同一个 y 轴上叠加三个曲线

Question

我想用三个不同的 sigma 值叠加正态分布的三个曲线。我这样做了：

curve(dnorm(x, mean(x), sd(x)), col = 2, lwd = 2)
par(new = TRUE)
curve(dnorm(x, mean(x), sd(x)/2), col = 3, lwd = 2)
par(new = TRUE)
curve(dnorm(x, mean(x), sd(x)*2), col = 4, lwd = 2)

结果是但我只想使用一个 y 轴刻度，所以这三个图是一个在另一个下面，而不是在同一个 y 轴上。另外我想扩大x轴的范围，例如从-3到3

Answer 1

首先通过设置plot参数type = "n"打开一个空白图形设备。然后add = TRUE 3条曲线。

plot(c(0, 1), c(0, 3), type = "n", xlab = "", ylab = "")
curve(dnorm(x, mean(x), sd(x)), col = 2, lwd = 2, add = TRUE)
curve(dnorm(x, mean(x), sd(x)/2), col = 3, lwd = 2, add = TRUE)
curve(dnorm(x, mean(x), sd(x)*2), col = 4, lwd = 2, add = TRUE)

Answer 2

您可以使用 yaxt 和 xaxt 从图表中删除 y 轴。

curve(dnorm(x, mean(x), sd(x)), col = 2, lwd = 2,ylab="My y axis name")
par(new = TRUE)
curve(dnorm(x, mean(x), sd(x)/2), col = 3, lwd = 2,yaxt='n',xaxt='n',ylab="")
par(new = TRUE)
curve(dnorm(x, mean(x), sd(x)*2), col = 4, lwd = 2,yaxt='n',xaxt='n',ylab="")

给予，

在同一个 y 轴上叠加三个曲线

Overlay three curves in the same y axis

r

curve

normal-distribution