2月20日,北京冬奥会圆满落幕,在无与伦比的盛会背后,有着许多志愿者的辛勤付出.在志愿者招募之时,甲、乙两所大学积极开展了志愿者选拔活动,现从两所大学参加测试的志愿者中分别随机抽取了10名志愿者的测试成绩进行整理和分析(成绩得分用x表示,共分成四组:A.
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E60%3C%2Fmn%3E%3Cmo%3E%E2%89%A4%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%26lt%3B%3C%2Fmo%3E%3Cmn%3E70%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
,B.
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E70%3C%2Fmn%3E%3Cmo%3E%E2%89%A4%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%26lt%3B%3C%2Fmo%3E%3Cmn%3E80%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
,C.
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E80%3C%2Fmn%3E%3Cmo%3E%E2%89%A4%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%26lt%3B%3C%2Fmo%3E%3Cmn%3E90%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
,D.
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmn%3E90%3C%2Fmn%3E%3Cmo%3E%E2%89%A4%3C%2Fmo%3E%3Cmi%3Ex%3C%2Fmi%3E%3Cmo%3E%26lt%3B%3C%2Fmo%3E%3Cmn%3E100%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
),下面给出了部分信息:
甲校10名志愿者的成绩(分)为:
.
乙校10名志愿者的成绩分布如扇形图所示,其中在C组中的数据为:
.
甲、乙校抽取的志愿者成绩统计表
| 甲校 | 乙校 |
平均数 | 87 | 87 |
中位数 | 87.5 | b |
方差 | ![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmsubsup%3E%3Cmi%3ES%3C%2Fmi%3E%3Cmrow%3E%3Cmi%3E%E7%94%B2%3C%2Fmi%3E%3Cmtext%3E%26nbsp%3B%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmn%3E2%3C%2Fmn%3E%3C%2Fmsubsup%3E%3C%2Fmrow%3E%3C%2Fmath%3E) | 79.4 |
众数 | c | 95 |
![](http://tikupic.21cnjy.com/2023/06/08/a2/74/a274d57c46cf5c3873b1914d7eb29296_m_124x158.png)