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Opened 13 years ago

Closed 13 years ago

#1586 closed defect (fixed)

Coeficiente de asimetría erróneo

Reported by: Pedro Gea Owned by: Pedro Gea
Priority: normal Milestone: Mantainance
Component: Kernel Version: 3.1
Severity: normal Keywords:
Cc:

Description

El coeficiente de asimetría (skewness) se calcula erróneamente.

El coeficiente se define como el tercer momento centrado estandarizado:

skew = E[((x-mu)/sigma)^3] = E[(x-mu)^3] / E[(x-mu)^2]^(3/2)

El problema parece estar en un cociente entero en el código (3/2=1).
Véase por ejemplo:

Set s = [[2,3,5,9]];
Real SetAsymmetry(s); // > 1.76
Real SetCenterMoment(s, 3)/(SetCenterMoment(s, 2)^1.5);  // > 0.657
Real SetCenterMoment(s, 3)/(SetCenterMoment(s, 2)^1);  // > 1.76

Change History (3)

comment:1 Changed 13 years ago by Pedro Gea

(In [4951]) Refs #1586

comment:2 Changed 13 years ago by Pedro Gea

(In [4952]) Refs #1586
Se corrige también en la rama 3.1.

comment:3 Changed 13 years ago by Pedro Gea

Resolution: → fixed
Status: new → closed
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