Question

I’m trying to arcsine squareroot data lying on [-1,1]. Using transf.arcsine from the metafor package produces NaNs when trying to squareroot the negative datapoints. Conceptually, I want to use arcsin(sgn(x)√|x|) i.e. square the absolute value, apply its previous sign, then arcsine transform it. The trouble is I have no idea how to begin doing this in R. Help would be appreciated.

Answer 1

x <- seq(-1, 1, length = 20)
asin(sign(x) * sqrt(abs(x)))

or as a function

trans.arcsine <- function(x){
  asin(sign(x) * sqrt(abs(x)))
}
trans.arcsine(x)