\begin{Schunk}
\begin{Sinput}
 dat$x1a <- dat$x1 - 5
 m2 <- lm(y ~ x1a, data = dat)
 plotSlopes(m2, plotx="x1a", interval="confidence", lwd = 0.4, axes = F)
 axis(1)
 axis(2, pos = 0)
 abline(v = 0)
\end{Sinput}
\end{Schunk}
