A distance AB is observed repeatedly using the same equipment and procedures, The results are in meters and are listed as $65\mathrm{.}401,65\mathrm{.}400,65\mathrm{.}402,65\mathrm{.}396,65\mathrm{.}409,65\mathrm{.}401,65\mathrm{.}396,65\mathrm{.}401,65\mathrm{.}400$ and $65\mathrm{.}403.$Calculate the most probable length.