[R] help with simple function

[Rui Barradas]

Hello,

You are missing a '*' in your first try.
(As for the second, in R parenthesis are round, not [])

sqrt(var(Y1) + var(Y2))^2 - 4*(var(Y1)*(var(Y2) - cov(Y1, Y2)^2))

This written as a function becomes

fun <- function(Y1, Y2)
	sqrt(var(Y1) + var(Y2))^2 - 4*(var(Y1)*(var(Y2) - cov(Y1, Y2)^2))

x1 <- rnorm(10)
x2 <- rnorm(10)
fun(x1, x2)


Hope this helps,

Rui Barradas

Em 17-03-2013 15:47, Miguel Eduardo Delgado Burbano escreveu:
> hello all
>
> I am writing a quite simple script to study dental wear patterns in humans
> and I wrote this function
>
> sqrt(var(Y1)+var(Y2))^2-4(var(Y1)*(var(Y2)-cov(Y1,Y2)^2)) but appear this
> error message
>
> Error: attempt to apply non-function
>
> alternatively I wrote this
>   sqrt(var(Y1)+var(Y2)^2)-4[(var(Y1)*(var(Y2)-cov(Y1,Y2)^2))]
>
> but this error message appear
>
> [1] NA
> Warning message:
> NAs introduced by coercion
>
> some suggestion to solve this?? thank you so much for your help
>
> Miguel
>
> 	[[alternative HTML version deleted]]
>
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