Predict y value for a given x in R

r linear-regression predict
Erica picture Erica · May 25, 2015 · Viewed 13.7k times · Source

I have a linear model:

mod=lm(weight~age, data=f2)

I would like to input an age value and have returned the corresponding weight from this model. This is probably simple, but I have not found a simple way to do this.

Answer

chepyle picture chepyle · May 25, 2015

Its usually more robust to use the predict method of lm:

f2<-data.frame(age=c(10,20,30),weight=c(100,200,300))
f3<-data.frame(age=c(15,25))
mod<-lm(weight~age,data=f2)
pred3<-predict(mod,f3)

This spares you from wrangling with all of the coefs when the models can be potentially large.

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