测量某项正态分布的医学指标n次，得其均值<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0.gif">和标准差S，求得区间(<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_1.gif">-t<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_2.gif">S/<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_3.gif">，<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_4.gif">+t<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_5.gif">S/<img border="0" alt="" src="https://img.weimei168.com/uploads/upimg/20230218/13999019_0_6.gif">)所代表的含义为