a=dx-t*s1; b=dx+t*s1;

printf(\在置信概率为0.95时，置信区间为[%.2f,%.2f]\\n\ } if(u==2) {

s1=s2/sqrt(n); t=t2[n-2];

printf(\ a=dx-t*s1; b=dx+t*s1;

printf(\在置信概率为0.99时，置信区间为[%.2f,%.2f]\\n\\n\ } return 0; }