[R] How to use different title in a loop

[Aval Sarri]

see ?paste

main = paste ("Main effect of ", variable)

> par(mfrow = c(n/2, 2))
> for ( i in 1:n)
> {
>        plot(1:J, y[i, 1: J], main = 'Main effect of X_i')
> }
>