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Econometria1-Transp-tema5-2

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f(p;Y1,…,Yn) =<br />

n<br />

Y<br />

i 1 p<br />

∑ = (1 − p)<br />

−∑<br />

(<br />

n<br />

) n Yi<br />

i i=<br />

1<br />

El EMV (MLE) maximiza la verosimilitud. Se suele trabajar con<br />

el logaritmo de la verosimilitud, ln[f(p;Y1,…,Yn)]:<br />

ln[f(p;Y1,…,Yn)] = ( ∑<br />

n<br />

) ( ∑<br />

n<br />

)<br />

i i<br />

dln f( p; Y1,..., Yn)<br />

dp<br />

Y ln( p) + n− Y ln(1 − p)<br />

i= 1 i=<br />

1<br />

1 ⎛ −1<br />

⎞<br />

+ −<br />

p<br />

⎜<br />

1−<br />

p<br />

⎟<br />

⎝ ⎠<br />

= (<br />

n<br />

) (<br />

n<br />

Y )<br />

i n Yi<br />

∑ ∑ = 0<br />

i= 1 i=<br />

1<br />

Resolviendo para p se obtiene el EMV (MLE); es decir, ˆ MLE<br />

p ,<br />

satisface,<br />

9-32

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