1/5单选题
难度：
1.有一组数据如下：3，a，4，6，7，它们的平均数是5，那么这组数据的方差是（ ）
| A | 10 |
| B |  |
| C |  |
| D | 2 |
- 提示1：
- 6aaW5YWI5qC55o2u566X5pyv5bmz5Z2H5pWw55qE5qaC5b+15rGC5Ye6YeeahOWAvO+8jOeEtuWQjuaKiuaVsOaNruS7o+WFpeaWueW3ruWFrOW8j+axguWHuuaVsOWAvO+8jg==
正确答案：RA==
6Kej77ya4oi1M++8jGHvvIw077yMNu+8jDfvvIzlroPku6znmoTlubPlnYfmlbDmmK8177yMPGJyPuKItO+8iDMrYSs0KzYrN++8icO3NT01PGJyPuKItGE9Ne+8jDxicj7iiLRzPHN1cD4yPC9zdXA+PTxpbWcgd2lkdGg9OSBoZWlnaHQ9NDIgc3JjPSJodHRwczovL3AyLnFpbmdndW8uY29tL0cxL00wMC9DNy9BNC9yQkFDRTFXYmtsNlNkSUJvQUFBQkt1QTBteFEyNzAucG5nIj5b77yINS0z77yJPHN1cD4yPC9zdXA+K++8iDUtNe+8iTxzdXA+Mjwvc3VwPivvvIg1LTTvvIk8c3VwPjI8L3N1cD4r77yINS0277yJPHN1cD4yPC9zdXA+K++8iDUtN++8iTxzdXA+Mjwvc3VwPl09Mu+8jjxicj7mlYXpgIlE77yO
2/5单选题
难度：
2.某村引进甲乙两种水稻良种，各选6块条件相同的实验田，同时播种并核定亩产，结果甲、乙两种水稻的平均产量均为550kg/亩，方差分别为S甲2=141.7，S乙2=433.3，则产量稳定，适合推广的品种为（ ）
| A | 甲、乙均可 |
| B | 甲 |
| C | 乙 |
| D | 无法确定 |
- 提示1：
- 5qC55o2u6aKY5oSP77yM5Y+v5b6X55Sy44CB5LmZ5Lik56eN5rC056i755qE5bmz5Z2H5Lqn6YeP55u45ZCM77yM54S25ZCO5q+U6L6D5Ye65a6D5Lus55qE5pa55beu55qE5aSn5bCP77yM
- 提示2：
- 5YaN5qC55o2u5pa55beu6LaK5bCP77yM5YiZ5a6D5LiO5YW25bmz5Z2H5YC855qE56a75pWj56iL5bqm6LaK5bCP77yM56iz5a6a5oCn6LaK5aW977yM5Yik5pat5Ye65Lqn6YeP56iz5a6a77yM6YCC5ZCI5o6o5bm/55qE5ZOB56eN5Li65ZOq56eN5Y2z5Y+v
正确答案：Qg==
6Kej77ya5qC55o2u6aKY5oSP77yM5Y+v5b6X55Sy44CB5LmZ5Lik56eN5rC056i755qE5bmz5Z2H5Lqn6YeP55u45ZCM77yMPGJyPuKItTE0MS4377ycNDMzLjPvvIw8YnI+4oi0UzxzdWI+55SyPC9zdWI+PHN1cD4yPC9zdXA+77ycUzxzdWI+5LmZPC9zdWI+PHN1cD4yPC9zdXA+77yMPGJyPuWNs+eUsuenjeawtOeou+eahOS6p+mHj+eos+Wumu+8jDxicj7iiLTkuqfph4/nqLPlrprvvIzpgILlkIjmjqjlub/nmoTlk4Hnp43kuLrnlLLnp43msLTnqLvvvI48YnI+5pWF6YCJ77yaQu+8jg==
3/5单选题
难度：
3.如果一组数据x1，x2，…，xn的方差是4，则另一组数据x1+3，x2+3，…，xn+3的方差是（ ）
| A | 4 |
| B | 7 |
| C | 8 |
| D | 19 |
- 提示1：
- 5qC55o2u6aKY5oSP5b6X77ya5pWw5o2ueDxzdWI+MTwvc3ViPu+8jHg8c3ViPjI8L3N1Yj7vvIzigKbvvIx4PHN1Yj5uPC9zdWI+55qE5bmz5Z2H5pWw6K6+5Li6Ye+8jOWImeaVsOaNrng8c3ViPjE8L3N1Yj4rM++8jHg8c3ViPjI8L3N1Yj4rM++8jOKApu+8jHg8c3ViPm48L3N1Yj4rM+eahOW5s+Wdh+aVsOS4umErM++8jOWGjeagueaNruaWueW3ruWFrOW8j+i/m+ihjOiuoeeulw==
正确答案：QQ==
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
4/5单选题
难度：
4.某市测得一周PM2.5的日均值（单位：微克/立方米）如下：31，30，34，35，36，34，31，对这组数据下列说法正确的是（ ）
| A | 众数是35 |
| B | 中位数是34 |
| C | 平均数是35 |
| D | 方差是6 |
- 提示1：
- 5qC55o2u5LyX5pWw44CB5bmz5Z2H5pWw44CB5Lit5L2N5pWw5ZKM5pa55beu55qE6K6h566X5YWs5byP5YiG5Yir6L+b6KGM6K6h566X
正确答案：Qg==
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
5/5单选题
难度：
5.在某次训练中，甲、乙两名射击运动员各射击10发子弹的成绩统计图如图所示，对于本次训练，有如下结论：①S甲2＞S乙2；②S甲2＜S乙2；③甲的射击成绩比乙稳定；④乙的射击成绩比甲稳定，由统计图可知正确的结论是（ ）
| A | ①③ |
| B | ①④ |
| C | ②③ |
| D | ②④ |
- 提示1：
- 5LuO5oqY57q/5Zu+5Lit5b6X5Ye655Sy5LmZ55qE5bCE5Ye75oiQ57up77yM5YaN5Yip55So5pa55beu55qE54m55oCn6L+b6KGM5rGC6Kej
正确答案：Qw==
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