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function y0 = ft(n,pt)
if pt < 0 || pt > 1
disp('输入有误,请输入[0 1]区间的数值')
elseif 0.5 <= pt && pt < 1
p1 = 2 * (1-pt);
tp = sqrt(n/fbeta(n,p1) - n);
elseif 0 < pt && pt < 0.5
p2 = 2*pt;
tp = -sqrt(n/fbeta(n,p2) - n);
elseif pt == 1
tp = inf;
else
tp = 0;
end
y0 = tp;
%beta分布的分位数计算
function y1=fbeta(n,p)
b = 1;
a = 0;
if abs(f(b,n,p)) < 1e-10
y1 = b;
else
while abs(b - a) > 1e-6
tb = (b + a)/2;
if abs(f(tb,n,p)) < 1e-10
y1 = tb;
break;
elseif f(tb,n,p) * f(b,n,p) < 0
a = tb;
else
b = tb;
end
end
y1 = tb;
end
%beta分布方程f = I(a,b) - p
function y2=f(z,n,p)
syms x t;
f1=int(t^(n/2-1)*(1-t)^(-0.5),0,'x');
f2=f1/beta(n/2,0.5);
f3=f2-p;
f3=subs(f3,x,z);
y2=eval('f3');
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