ftest.c

来自「Numerical Recipes Software 提供的算法子程序集」· C语言 代码 · 共 24 行

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;
}
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