问答题
设有一组来自正态总体的样本观测值:
0.497,0.506,0.518,0.524,0.488,0.510,0.510,0.515,0.512, ⑴已知,求的置信区间(设置信度为0.95)
⑵未知,求的置信区间(设置信度为0.95)