How to change the axis and legend on loess.ancova function

Question

I am trying to do an ANCOVA test of a specific dataset using fANCOVA package and the loess.ancova function.

loess.ancova(y=dt$response,x=dt$var1,group=dt$species,family= "gaussian",method="Speckman", plot = T)

After calling the code I get a plot similar to this

How can I change the legend and the axis names? I tried using

loess.ancova(y,x,group,...,plot=T, xlab="var1", ylab="response")

but nothing changed, since that failed I have no idea how to even try to change the legend

Any help would be appreciated

Answer 1

one possibility is to save the result of your loess.ancova call:

result <- loess.ancova(y=dt$response,
                       x=dt$var1,
                       group=dt$species,
                       family= "gaussian",
                       method="Speckman",
                       plot = T
                       )

Inspection of the result with str(result) shows that it contains an item "smooth.fit":

> str(result)
List of 2
 $ linear.fit: num [1:3, 1] 5.88 -3.01 -6.1
  ..- attr(*, "dimnames")=List of 2
  .. ..$ : chr [1:3] "(Intercept)" "group2" "group3"
  .. ..$ : NULL
 $ smooth.fit:List of 18
  ..$ n        : int 245
  ..$ fitted   : num [1:245
## [truncated]

... which you can plot, using the desired base plot() arguments:

result$smooth.fit |> plot(xlab = 'my x-axis label', ...)