The Following Frequency Distribution Shows the GMAT Scores of a Sample

The following frequency distribution shows the GMAT scores of a sample of MBA students.
$\begin{array}{ll}\text { GMAT Score }&\text { Frequency }\\300 \mathrm{up} \text { to } 400 & 1 \\400 \mathrm{up} \text { to } 500 & 5 \\500 \mathrm{up} \text { to } 600 & 9 \\600 \mathrm{up} \text { to } 700 & 3 \\700 \mathrm{up} \text { to } 800 & 2\end{array}$ For the above data, compute the mean GMAT score.