evalPoly <- function( x, coeff ) {
    if ( length( coeff ) < 1 ) return( c(0) )
    termSum <- 0
    for ( i in 1:length(coeff) ) {
        termSum <- termSum + coeff[i] * x^(i-1)
    }
    return( termSum )
}

soTest <- function() {
    coeff <- c( 1, 2, -3, 4 )
    x <- 1:8
    y <- evalPoly( x, coeff )
    plot( x, y )
    text( 2, 1600, parse( text="1+2*x-3*x^2+4*x^3" ), adj=0 )
    text( 2, 1400, parse( text="Model:  y = 1+2*x-3*x^2+4*x^3" ), adj=0 )
}