Earnings per share. The earnings per share $($in dollars$)$ for $12$ companies selected at random from the list of Fortune $500$ companies are:

$\backslash$table$[[0\mathrm{.}57,0\mathrm{.}71,7\mathrm{.}68,6\mathrm{.}67],[5\mathrm{.}37,4\mathrm{.}01,1\mathrm{.}64,0\mathrm{.}86],[2\mathrm{.}02,4\mathrm{.}93,8\mathrm{.}27,8\mathrm{.}28]]$

a$.$ Find the mean of the earnings per share. $

$($Type an integer or a decimal. Round to two decimal places.$)$

b$.$ Find the standard deviation of the earnings per share. $

$($Type an integer or a decimal. Round to two decimal places.$)$