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A. Juriˇ<strong>si</strong>ć in V. Batagelj: Verjetnostni račun in statistika 202<br />

✬<br />

✫<br />

Naloga<br />

Pri ˇstudiju upora Y strukturnega elementa in <strong>si</strong>le X, ki deluje nanj,<br />

smatramo za slučajni spremenljivki. Verjetnost napake nf je definirana z<br />

P (Y ≤ X). Predpostavimo, da je<br />

p(x, y) = abe −(ax+by)<br />

za (x, y) > 0<br />

in p(x, y) = 0 <strong>si</strong>cer, pri čemer sta a in b poznani pozitivni ˇstevili. ˇZelimo<br />

izračunati nf , tj.<br />

<br />

F (x, y) = p(x, y) dydx,<br />

R<br />

kjer je območje R določeno s pogojem Y ≤ X. Ker slučajni spremenljivki<br />

X in Y zavzameta samo pozitivne vrednosti, velja<br />

∞ ∞<br />

a b e −(ax+by) ∞ x<br />

dx dy = a b e −(ax+by) dy dx.<br />

nf =<br />

0<br />

y<br />

Univerza v Ljubljani ▲<br />

❙ ▲<br />

▲<br />

0<br />

0<br />

● ❙ ▲<br />

▲<br />

☛ ✖<br />

▲<br />

✩<br />

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