\begin{Schunk}
\begin{Sinput}
 ## plot power by sample size
 plot(first ~ N, data = rates, type = "l", lwd = 2, ylim = 0:1)
 abline(h = .8, col = "darkgreen", lty = "dashed")
 lines(momIQ ~ N, data = rates, col = "red", lwd = 2, lty = 2)
 lines(dadIQ ~ N, data = rates, col = "blue", lwd = 2, lty = 3)
 legend("bottomright", legend = c("first", "momIQ", "dadIQ"),
         col = c("black" , "red", "blue"), lty = c(1,2,3))
\end{Sinput}
\end{Schunk}
