题干

某研究型学习小组调查研究学生使用智能手机对学习的影响.部分统计数据如表:

使用智能手机

不使用智能手机

总计

学习成绩优秀

4

8

12

学习成绩不优秀

16

2

18

总计

20

10

30

附表:

P(K2≥k0

0.15

0.10

0.05

0.025

0.010

0.005

0.001

k0

2.072

2.706

3.841

5.024

6.635

7.879

10.828

经计算K2的观测值为10,则下列选项正确的是(   )

A:有99.5%的把握认为使用智能手机对学习有影响

B:有99.5%的把握认为使用智能手机对学习无影响

C:在犯错误的概率不超过0.001的前提下认为使用智能手机对学习有影响

D:在犯错误的概率不超过0.001的前提下认为使用智能手机对学习无影响

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答案(点此获取答案解析)

A

同类题3

阅读理解

    During all this time I never stopped thinking about escape. When I traveled across to the other side of the island, I could see the other islands, and I said to myself, "Perhaps I can get there with a boat. Perhaps I can get back to England one day."

    So I decided to make myself a boat. I cut down a big tree, and then began to make a long hole in it. It was hard work, but about six months later, I had a very fine canoe (独木舟). Next, I had to get it down to the sea. How silly I was! Why didn't I think before I began work? Of course, the canoe was too heavy. I couldn't move it! I pulled and pushed and tried everything, but it didn't move. I was very unhappy for a long time after that.

    That happened in my fourth year on the island. In my sixth year I did make myself a smaller canoe, but I did not try to escape in it. The boat was too small for a long journey, and I did not want to die at sea. The island was my home now, not my prison, and I was just happy to be alive. A year or two later, I made myself a second canoe on the other side of the island. I also built myself a second house there, and so I had two homes.

    My life was still busy from morning to night. There were always things to do or to make. I learnt to make new clothes for myself from the skins of dead animals. They looked very strange, it is true, but they kept me dry in the rain.

    I kept food and tools at both my houses, and also wild goats. There were many goats on the island, and I made fields with high fences to keep them in. They learnt to take food from me, and soon I had goats' milk to drink every day. I also worked hard in my corn (玉米) fields. And so many years went by.