Calcualte a range (-z,z), whose probability is dA in normal distribution
double invprob( double dA )
Returns z value such that the area under the normal curve between -z and +z is dA.
EX1
void invprob_ex1() { double dz,dA=0.6826895; dz=invprob(dA); // results in dz==1 }
norminv, prob
origin.h