中国国家统计局2019年9月30日发布数据显示,2019年9月中国制造业采购经理指数
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmo%3E%28%3C%2Fmo%3E%3Cmrow%3E%3Cmi%3EP%3C%2Fmi%3E%3Cmi%3EM%3C%2Fmi%3E%3Cmi%3EI%3C%2Fmi%3E%3C%2Fmrow%3E%3Cmo%3E%29%3C%2Fmo%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
为49.8%,反映出中国制造业扩张步伐有所加快.以新能源汽车、机器人、增材制造、医疗设备、高铁、电力装备、船舶、无人机等为代表的高端制造业突飞猛进,则进一步体现了中国制造目前的跨越式发展.已知某精密制造企业根据长期检测结果,得到生产的产品的质量差服从正态分布
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmi%3EN%3C%2Fmi%3E%3Cmn%3E%28%3C%2Fmn%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmsup%3E%3Cmrow%3E%3Cmtext%3E%CF%83%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsup%3E%3Cmn%3E%29%3C%2Fmn%3E%3C%2Fmath%3E)
, 并把质量差在
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E%28%3C%2Fmn%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmtext%3E%CF%83%3C%2Fmtext%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmtext%3E%CF%83%3C%2Fmtext%3E%3Cmn%3E%29%3C%2Fmn%3E%3C%2Fmath%3E)
内的产品称为优等品,质量差在
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E%28%3C%2Fmn%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmtext%3E%CF%83%3C%2Fmtext%3E%3Cmn%3E++%EF%BC%8C+%3C%2Fmn%3E%3Cmtext%3E%CE%BC%3C%2Fmtext%3E%3Cmo%3E%2B%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmtext%3E%CF%83%3C%2Fmtext%3E%3Cmn%3E%29%3C%2Fmn%3E%3C%2Fmath%3E)
内的产品称为一等品,优等品与一等品统称为正品,其余范围内的产品作为废品处理.现从该企业生产的正品中随机抽取1000件,测得产品质量差的样本数据统计如下:
![](http://tikupic.21cnjy.com/2022/03/29/ab/eb/abebda8e8e2319e1903e2b5fd9ac3b9d_377x229.png)