How to find the best regression model fit for your plot

Question

let's say I wish to fit a regression model to disp ~ drat from the mtcars dataset. Is there a package I can use that can tell me what type of regression I should use e.g. linear, polynomial, bayesian etc.?

ggplot(mtcars, aes(disp, drat)) +
  geom_point() +
  facet_wrap(~cyl)  

Answer 1

Pointing out the suggestion from @Roland you should do some exploratory and visual analysis to understand your data first. You can try with stat_smooth() and then decide what kind of model you want to fit:

library(ggplot2)
#Code
ggplot(mtcars, aes(disp, drat)) +
  geom_point() +
  facet_wrap(~cyl)+
  stat_smooth(se=F)+
  stat_smooth(color='magenta',method = 'lm',se=F)

Output: