How to backtransform squareroot transformed data in visreg in R

Question

I've been trying to backtransfrom my squareroot transformed data in visreg in R but I can't find the right command for trans=. In the visreg guidance it only discusses using trans=exp to backtransform log transformed data. How do I specify I want to square the values using trans= ?

Here is my code:

m5<-lm(sqrt(forearm_m)~pro_two +lat_n +year +sat, data=pleaur_w) Anova(m5) summary(m5) plot(m5) visreg(m5, "year", xlab="Year", ylab="Forearm (cm)", trans=, main="P. auritus", line=list(col="black"), cex.main=1.8, cex.lab=1.8, plot=TRUE)

Answer 1

You should be able to define whatever function you want for the trans= parameter:

square <- function(x){
  return(x**2)
}

visreg(m5, "year", xlab="Year", ylab="Forearm (cm)", trans=square, main="P. auritus",
       line=list(col="black"), cex.main=1.8, cex.lab=1.8, plot=TRUE)