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2025-02-Numerical/lib/nr/k_and_r/recipes/ftest.c
2025-09-12 18:55:25 +09:00

24 lines
430 B
C

void ftest(data1,n1,data2,n2,f,prob)
float *f,*prob,data1[],data2[];
unsigned long n1,n2;
{
float betai();
void avevar();
float var1,var2,ave1,ave2,df1,df2;
avevar(data1,n1,&ave1,&var1);
avevar(data2,n2,&ave2,&var2);
if (var1 > var2) {
*f=var1/var2;
df1=n1-1;
df2=n2-1;
} else {
*f=var2/var1;
df1=n2-1;
df2=n1-1;
}
*prob = 2.0*betai(0.5*df2,0.5*df1,df2/(df2+df1*(*f)));
if (*prob > 1.0) *prob=2.0-*prob;
}