Peter - 4 months ago 14

R Question

I am trying to put two regression lines into the same plot. I can do it by using the code below but with the same color of line:

`model1 <- glm(species~logarea, family=poisson, data=fish)`

model2 <- glm.nb(species~logarea, data=fish)

plot(species~logarea,data=fish)

lines(fitted(model1)[order(logarea)]~sort(logarea),data=fish)

lines(fitted(model2)[order(logarea)]~sort(logarea),data=fish)

I am thinking to use ggplot to replicate above plot so I can display different line with different color. But I could not figure out how to do it.

I only finished the first step which is drawing the scatter plot, but don't know how to add lines on it.

`ggplot(fish,aes(fish$logarea,fish$SPECIES))+geom_point()`

I did some search and I understand that I can use geom_smooth(method = "glm") to generate regression line. But it seems it is not based on the model I built.

Could anyone shed some light on this?

Many thanks.

Answer