Business case estimation accuracy is usually very low, with the actual confidence interval often higher then 50%, as no detailed functional and project analysis is usually performed.
业务案例评估的精度经常很低，由于通常不能完成细节的功能分析，可信区间通常高达50%。
2
Conclusion Normal distribution theory may be used in the intervalestimation and hypothesis testing of rank sum.
结论对秩和与秩和比可以应用正态分布理论作区间估计和假设检验。
3
Results: Deduce the formula of the intervalestimation of small sample and large sample.