A distance AB

is observed repeatedly using the same equipment and procedures, and the results, in meters, are listed:

$57\mathrm{.}401,57\mathrm{.}400,57\mathrm{.}402,57\mathrm{.}396,57\mathrm{.}401,57\mathrm{.}396,57\mathrm{.}401,$ and $57\mathrm{.}404.$ Calculate the line$$s most probable length.