$\text {The following questions refer to this regression equation, (standard errors in parentheses.)}$

$\text {The following questions refer to this regression equation, (standard errors in parentheses.)}$
$$\mathrm { Q } = 8,400 - 10 \mathrm { P } + 5 \mathrm {~A} + 4 \mathrm { Px } + 0.05 \mathrm { I } , ( 1,732 ) ( 2.29 ) ( 1.36 ) ( 1.75 ) 0.15 )$$
$\begin{array} { l } \mathrm { R } ^ { 2 } = 0.65 \\\mathrm {~N} = 120 \\\mathrm {~F} = 35.25\end{array}$
$\text {Standard error of estimate \(= 34.3\)}$
$\text {\(Q =\) Quantity demanded}$
$\text {\(\mathrm { P } =\) Price \(= 1,000\)}$
$\text {\(\mathrm { A } =\) Advertising expenditures, in thousands \(= 40\)}$
$\text {\(\mathrm { PX } =\) price of competitor's good \(= 800\)}$
$\text {\(\mathrm { I } =\) average monthly income \(= 4,000\)}$
-How is the R² value calculated,and what information does this give you?