Given the following analysis of variance table, compute mean squares for between groups and within groups. Compute the $F$ ratio and test the hypothesis that the group means are equal.
$$
\begin{array}{lcc}
\hline \begin{array}{l}
\text { Source of } \\
\text { Variation }
\end{array} & \begin{array}{c}
\text { Sum of } \\
\text { Squares }
\end{array} & \begin{array}{c}
\text { Degrees of } \\
\text { Freedom }
\end{array} \\
\hline \text { Between groups } & 1,000 & 2 \\
\text { Within groups } & 743 & 15 \\
\text { Total } & 1,743 & 17 \\
\hline
\end{array}
$$