void ftest(float data1[], unsigned long n1, float data2[], unsigned long n2,	float *f, float *prob){	void avevar(float data[], unsigned long n, float *ave, float *var);	float betai(float a, float b, float x);	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;}