Question

I expected the following code to return the lower and upper bounds of a 95% confidence interval:

confint95 = function(mean, se)
{
  confint = abs(se*1.96)
  lower = abs(mean-cint)
  upper = abs(mean+cint)
  return(lower,upper) 
}

But this gives this message:

Error in return(lower, upper) : multi-argument returns are not permitted

How can I set function to return the lower and upper bounds of a 95% confidence interval?

Answer 1

Function will return the last expression. If you think for a moment without return. If you gave the function as the last expression to be evaluated

lower, upper

it would produce an error. If you have IDE it would also probably complain about a syntax error. You would solve that by combining the two elements with a c as @Andrie indicated. Ergo, you need to pass a single object. I often use lists to output different data structures. In your case, a vector is more than sufficient.