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Slika - Shrani.si

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A. Juriˇ<strong>si</strong>ć in V. Batagelj: Verjetnostni račun in statistika 624<br />

✬<br />

✫<br />

. . . Linearni model<br />

Določimo jo po načelu najmanjˇ<strong>si</strong>h kvadratov z minimizacijo funkcije<br />

f(a, b) =<br />

n<br />

(yi − (bxi + a)) 2 .<br />

i=1<br />

Naloga zadoˇsča pogojem izreka. Iz pogoja ∇P = 0 dobimo enačbi<br />

z reˇ<strong>si</strong>tvijo<br />

∂f<br />

∂a =<br />

∂f<br />

∂b =<br />

n<br />

2(yi − (bxi + a)) = 0,<br />

i=1<br />

n<br />

2(yi − (bxi + a))xi = 0,<br />

i=1<br />

b = n xy − x y<br />

n x2 − ( 1<br />

<br />

, a = y − b x .<br />

x) 2 n<br />

Univerza v Ljubljani ▲<br />

❙ ▲<br />

▲<br />

● ❙ ▲<br />

▲<br />

☛ ✖<br />

▲<br />

✩<br />

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