\begin{Schunk}
\begin{Sinput}
 plotCurves(glm1, plotx="x2", interval="confidence")
\end{Sinput}
\begin{Soutput}
rockchalk:::predCI: model's predict method does not return an interval.
 We will improvize with a Wald type approximation to the confidence interval 
\end{Soutput}
\end{Schunk}
