/*?gdb?output?? 程序還未調試成功：http://ubuntuforums.org/archive/index.php/t-412096.html ? */

/*(gdb)?run
Starting?program:?/home/nrh1/code/testt

Program?received?signal?SIGSEGV,?Segmentation?fault.
0x0804967f?in?var?()???*/

/*?function?to?calculate?ttest?ttest.c
*/
#include?<stdio.h>
#include?<math.h>

#define?square(x)?(x*x)
void?ttest(double?*data1,?unsigned?int?n1,?double?*data2,?unsigned?int?n2,?double?*tstatistic,?double?*tprob);
int?main()

{

/*?declare?arrays?of?x?and?y?data?from?statistical?methods?in?cell?biology?2nd?edition?pg?45*/
double?a[8]=?{3.2,1.6,5.7,2.8,5.5,1.2,6.1,2.9};
double?b[8]=?{3.8,1.0,8.4,3.6,5.0,3.5,7.3,4.8};
unsigned?int?na=8;
unsigned?int?nb=8;
double*?t;
double?*prob;

ttest(?a,?na,?b,?nb,?&t,?&prob);
printf("tvalue?%f\n",?&t);

printf("tvalue?%f\n",?&prob);
}?/*?program?closing?brace????*/

/*uses?part?of?stats?lib?stats.c?the?relevant?functions?are?shown?below?ftest?code?is?nt?mine?but?works?very?well?I've?used?it?in?other?contexts???*/

/*
ttest?assumes?homogenity?of?variance,?uses?ftest?probability?code?to?calculate?probability?of?the?significance?of?the?t?statistic

*/


double?var(double?*data,?unsigned?int?n)
{
unsigned?int?i;
double?average=0.0;
double?s,?temp,?var;

for?(i=0;?i<n;?n++)
average=average+data[n];?/*?calculate?average???*/

average=average/n;

var=temp=s=0.0;?/*?now?variance??*/
for?(i=0;?i<n;?n++)
{
s=data[n]-average;
temp=temp+s;
var=var+(s*s);

}
return?(var-temp*temp/n)/(n-1);
}?/*?function?closing?brace???*/
/*?end?of?function?*/

void?ttest(double?*data1,?unsigned?int?n1,?double?*data2,?unsigned?int?n2,?double?*tstatistic,?double?*tprob)
{

double?nmean(unsigned?int?count,?double?*data);?/*?function?declarations?within?function????*/
double?pof(double?F,?unsigned?int?df1,?unsigned?int?df2);
double?var(double?*data,?unsigned?int?n);
double?svar=0.0;
double?var1=0.0;
double?var2=0.0;
double?mean1=0.0;
double?mean2=0.0;
double?df=0.0;
/*double?*tstatistic=0.0;??*/
/*double?*tprob=0.0?????*/

mean1=nmean(n1,?data1);?/*calculate?means?for?individual?data?sets????*/
mean2=nmean(n2,?data2);
var1=var(data1,?n1);?/*calculate?variances?for?individual?data?sets?????*/
var2=var(data2,?n2);
df=n1+n2-2;?/*?calculate?overall?df?????????????????*/
svar=((n1-1)*var1+(n2-1)*var2)/df;?/*?pooled?variance??*/
*tstatistic=(mean1-mean2)/sqrt(svar*(1.0/n1+1.0/n2));?/*?calculate?t?value????*/
*tprob=pof(((*tstatistic)*(*tstatistic)),?1,?df);?/*probability????????*/
}?/*?function?closing?brace??????*/

/*?end?of?function?*/


/*FUNCTION?pof:?probability?of?F?*/
/*ALGORITHM?Compute?probability?of?F?ratio.

*/

/*
example?if?F=1.432923?and?df1=3?and?df2=5?p=0.337564
*/
double?pof(double?F,?unsigned?int?df1,?unsigned?int?df2)
{

int?i,?j;
int?a,?b;
double?w,?y,?z,?d,?p;

if?(F?<?F_EPSILON?||?df1?<?1?||?df2?<?1)
p=1.0;
else
{
a?=?df1%2???1?:?2;
b?=?df2%2???1?:?2;
w?=?(F?*?df1)?/?df2;

z?=?1.0?/?(1.0?+?w);
if?(a?==?1)
if?(b?==?1)
{
p?=?sqrt?(w);
y?=?I_PI;?/*?1?/?3.14159?*/
d?=?y?*?z?/?p;
p?=?2.0?*?y?*?atan?(p);
}
else
{
p?=?sqrt?(w?*?z);
d?=?0.5?*?p?*?z?/?w;
}
else?if?(b?==?1)
{
p?=?sqrt?(z);
d?=?0.5?*?z?*?p;
p?=?1.0?-?p;
}
else
{
d?=?z?*?z;
p?=?w?*?z;
}
y?=?2.0?*?w?/?z;

for?(j?=?b?+?2;?j?<=?df2;?j?+=?2)
{
d?*=?(1.0?+?a?/?(j?-?2.0))?*?z;
p?=?(a?==?1???p?+?d?*?y?/?(j?-?1.0)?:?(p?+?w)?*?z);
}

y?=?w?*?z;
z?=?2.0?/?z;
b?=?df2?-?2;
for?(i?=?a?+?2;?i?<=?df1;?i?+=?2)
{
j?=?i?+?b;
d?*=?y?*?j?/?(i?-?2.0);
p?-=?z?*?d?/?j;
}
/*?correction?for?approximation?errors?suggested?in?certification?*/
if?(p?<?0.0)
p?=?0.0;
else?if?(p?>?1.0)
p?=?1.0;
p=?(1.0-p);
return?p;
}
return?p;
}

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