Answer
$s_e=229.547$
Work Step by Step
$ŷ =2.531x−399$
$s_e=\sqrt {\frac{Σ(y_i-ŷ_i)^2}{n-2}}=\sqrt {\frac{[650-(2.531\times500−399)]^2+[1215-(2.531\times588−399)]^2+[2000-(2.531\times1000−399)]^2+[1655-(2.531\times688−399)]^2+[1250-(2.531\times825−399)]^2+[2700-(2.531\times1259−399)]^2+[1200-(2.531\times650−399)]^2+[1250-(2.531\times560−399)]^2+[2350-(2.531\times1073−399)]^2+[3300-(2.531\times1452−399)]^2+[1305-(2.531\times3100−399)]^2}{11-2}}=229.547$
