题干

某中学开展“唱红歌”比赛活动,九年级(1)、(2)班根据初赛成绩,各选出5名选手参加复赛,两个班各选出的5名选手的复赛成绩如图所示.

(1)根据图示填写下表;

班级

平均数(分)

中位数(分)

众数(分)

九(1)


85


九(2)

85


100

(2)结合两班复赛成绩的平均数和中位数,分析哪个班级的复赛成绩较好;

(3)计算两班复赛成绩的方差.

上一题 下一题 0.0难度 选择题 更新时间:2018-01-20 12:56:57

答案(点此获取答案解析)

解:(1)由图可知九(1)班5名选手的复赛成绩为:75、80、85、85、100,

九(2)班5名选手的复赛成绩为:70、100、100、75、80,

∴九(1)的平均数为(75+80+85+85+100)÷5=85,

九(1)的中位数为85,

九(1)的众数为85,

把九(2)的成绩按从小到大的顺序排列为:70、75、80、100、100,

∴九(2)班的中位数是80;

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