题干

某校对甲、乙两个文科班的数学考试成绩进行分析,规定:大于或等于120分为优秀,120分以下为非优秀.统计成绩后,得到如下的2×2列联表.根据列联表的数据判断有多少的把握认为“成绩与班级有关系”.(   )

优秀

非优秀

合计

甲班

10

50

60

乙班

20

30

50

合计

30

80

110

K2≥k

0.100

0.050

0.025

0.010

0.001

k

2.706

3.841

5.024

6.635

10.828

参考公式与临界值表:K2=

n
(
a
c
b
c
)
2
(
a
+
b
)
(
c
+
d
)
(
a
+
c
)
(
b
+
d
)

A:90%

B:95%

C:99%

D:99.9%

上一题 下一题 0.0难度 选择题 更新时间:2010-11-15 10:13:35

答案(点此获取答案解析)

B

同类题5


Dear Boarding Students,

      At this time of school year, we can feel some students begin to experience excitement as the summer vacation comes. But some others still don't want to start packing. I once again ask for your attention as we will have summer camps for the new students. There is much work to be done in packing and cleaning-up,especially during exam week.

              ▲      Each student will get a task list and each task has a deadline(期限). The dorm(寝室)teachers will work with each student each night to make sure you are getting the tasks done on time. It would be helpful if your parents encourage you to do a little packing and cleaning from now on. It means you can take the posters off the wall,pack up winter clothes,return all borrowed books to the library,etc. Spending twenty minutes a day on your tasks will make the last week of the term very easy,and you can spend more time on the important preparation for exams. If you plan to travel home,I'd like to remind you to take some of your belongings with you.

      The coming weekend is a "closed weekend". During that time no one is allowed to leave school. After packing we need to prepare the dorms for moving out,and store(储藏)students' large belongings.

      The last exam is on Thursday and all students leave after their exam. The dorm will remain open until 5 p. m. on Friday for those students that could not get a ride or flight. Please let us know if you need transportation to the airport.

      Thank you again for all your attention during the last,busy month of school. As always,you,welcome to call or email me with any questions.

    Peter Margio

    Director of Campus Life

      453-757-2630

    pmargio@ baylinschool. com