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ggplot Fit Line and Lattice Fit Line in R

Mollie

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Let’s add a fit line to a scatterplot!

Fit Line in Base Graphics

Here’s how to do it in base graphics:
< !-- HTML generated using hilite.me -->
ols <- lm(Temp ~ Solar.R,
  data = airquality)

summary(ols)

plot(Temp ~ Solar.R,
  data = airquality)
abline(ols)

Fit line in base graphics in R



Fit Line in ggplot

And here’s how to do it in ggplot:
< !-- HTML generated using hilite.me -->
library(ggplot2)
ggplot(data = airquality,
    aes(Solar.R, Temp)) + 
  geom_point(pch = 19) + 
  geom_abline(intercept = ols$coefficients[1],
    slope = ols$coefficients[2])

You can access the info from your regression results through ols$coefficients.
Fit line in ggplot in R

Fit Line in Lattice

In lattice, it’s even easier. You don’t even need to run a regression; you can just add to the type option.

< !-- HTML generated using hilite.me -->
library(lattice)

xyplot(Temp ~ Solar.R,
  data = airquality,
  type = c("p", "r"))

Fit Line in Lattice in R
The code is available in a gist.

References


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