问题描述:

I'm trying to get a scatterplot graph showing 2 regression lines so that interaction effects are clear.

My code is as follows:

`lm <- lm(Cage_Int ~ Sex + AVP_mvBNST_ros_caud + Sex:AVP_mvBNST_ros_caud, data=data)`

plot(data$Cage_Int, data$AVP_mvBNST_ros_caud, xlab="V1aR in BNSTmv",

ylab="Interaction time", col=colors, pch=20)

curve(cbind(x,1,x,1*x) %*% coef(lm), add=TRUE, col="red")

curve(cbind(1,0,x,0*x) %*% coef(lm), add=TRUE, col="blue")

this gives me the right scatterplot graph,but the regression lines are not showing, which is not what I want (I want both regression lines to show, one for sex=0 and one for sex=1)

Thanks a lot in advance!

Run the regression with `sex=0`

and `sex=1`

and create two separate linear models using `lm()`

. Once you define the two models `model1 = lm(<insert equation>)`

and `model2 = lm(<insert second equaiton>)`

, you can simply ad a line using `abline()`

or, in this case:

```
abline(model1)
abline(model2)
```

after the plot function and that should do the trick. You can add colors and different line effects using `abline()`

as well.