fixed some index entries

regression/lecture/regression.tex

@@ -76,8 +76,8 @@ large deviations.
 
 \begin{exercise}{meanSquareError.m}{}\label{mseexercise}%
   Implement a function \code{meanSquareError()}, that calculates the
-  \emph{mean square distance} bewteen a vector of observations ($y$)
-  and respective predictions ($y^{est}$).  \pagebreak[4]
+  \emph{mean square distance} between a vector of observations ($y$)
+  and respective predictions ($y^{est}$).
 \end{exercise}