\begin{Schunk}
\begin{Sinput}
 m2apsts <- testSlopes(m2aps)
\end{Sinput}
\begin{Soutput}
Values of x2 OUTSIDE this interval:
       lo        hi 
-3.193191 24.524897 
cause the slope of (b1 + b2*x2)x1 to be statistically significant
\end{Soutput}
\begin{Sinput}
 plot(m2apsts)
\end{Sinput}
\end{Schunk}
