what is the meaining of both Std$.$ Error and Sig in the follwoing iformation Model Unbaselineized Coefficients Baselineized Coefficients t Sig.

B Std$.$ Error Beta

$1($Constant$)62\mathrm{.}2693\mathrm{.}03720\mathrm{.}501\mathrm{.}000$

Total cholesterol $($mmol$/$L$)$ at baseline $1\mathrm{.}619\mathrm{.}651\mathrm{.}1112\mathrm{.}487\mathrm{.}013$