Can someone tell me a proper call to a procedure, in this case, pnorm. In what follows, I had expected a = b, but they are not equal. What are wrong with first call and second call? Thank you! try<-function(x,log.p=FALSE){ a<-pnorm(x,log.p) # first call b<-pnorm(x,log.p=log.p) # second call list(a=a,b=b) } try(x=1.2,log.p=TRUE)$a try(x=1.2,log.p=TRUE)$b