CODEWITHSUNDEEP
rregression
Adrian
Adrian

Reputation: 9793

R: adding multiple regression lines and loess curve to plot

mod = lm(iris$Petal.Length ~ iris$Petal.Width + iris$Species)
plot(iris$Petal.Length ~ iris$Petal.Width, col = iris$Species)
abline(mod)

enter image description here

Here I'm stratifying Species and I want to plot 3 regression lines, one for each species. abline(mod) seems to only add one line only. Also, what if I wanted to add LOESS curve?

Upvotes: 2

Views: 613

Answers (2)

RoyalTS
RoyalTS

Reputation: 10203

A ggplot one-liner:

library(ggplot2)

ggplot(iris, aes(Petal.Width, Petal.Length, color=Species)) + geom_point() + geom_smooth(method='lm', formula=y~x)

Leave out the arguments to geom_smooth() and you would get the LOESS line. However, the data here are so scant that this fails.

Upvotes: 3

AidanGawronski
AidanGawronski

Reputation: 2085

mod = lm(iris$Petal.Length ~ iris$Petal.Width + iris$Species)
plot(iris$Petal.Length ~ iris$Petal.Width, col = iris$Species)
abline(coefficients(mod)[1], coefficients(mod)[2])
abline(coefficients(mod)[1], coefficients(mod)[3])
abline(coefficients(mod)[1], coefficients(mod)[4])

Upvotes: 2

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