【简答题】
用某种方法测定一纯化合物中组分A的的质量分数,共9次,求得组分A的平均值<img src="https://nimg.ppkao.com/2019-04/wangjing/2019042716490284798.jpg?sign=d69049d04dbea114db7bdac846be6823&t=62d5d041" />=60.68%,标准差s=0.042%。已知μ=60.66%,t<sub>0.05,8</sub>=2.31<br /> (1)平均值的置信区间为多少?<br /> (2)<img src="https://nimg.ppkao.com/2019-04/wangjing/2019042716490284798.jpg?sign=d69049d04dbea114db7bdac846be6823&t=62d5d041" />与μ之间有无显著差异?