$65\mathrm{.}401$

$65\mathrm{.}402$

$65\mathrm{.}4$

$65\mathrm{.}396$

$65\mathrm{.}401$

$65\mathrm{.}396$

$65\mathrm{.}401$

$65\mathrm{.}404$

Calculate the most probable length

Calculate the standard deviation

Calculate the standard deviation of the mean