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Regressione lineare semplice: inferenza - Economia

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Teorema di Gauss-Markov<br />

Il teorema di Gauss-Markov-Prova<br />

Sia<br />

quindi<br />

<br />

i<br />

a 2 i = <br />

<br />

âidi =<br />

i<br />

i<br />

ai = âi + di<br />

(âi + di) 2 = <br />

<br />

i (Xi − ¯ X)di<br />

<br />

i (Xi − ¯ X) 2<br />

i<br />

â 2 i + 2 <br />

i<br />

âidi + <br />

<br />

i =<br />

diXi − ¯ X <br />

i di<br />

<br />

i (Xi − ¯ X) 2<br />

<br />

( aiXi − âiXi) − ¯ X ( ai − âi) <br />

=<br />

= 0<br />

<br />

i (Xi − ¯ X) 2<br />

Rossi <strong>Regressione</strong> <strong>lineare</strong> <strong>semplice</strong> Econometria - 2013 42 / 60<br />

i<br />

d 2 i

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