题目内容
【题目】某一射手射击所得的环数ξ的分布列如下：
ξ | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
P | 0.02 | 0.04 | 0.06 | 0.09 | 0.28 | 0.29 | 0.22 |
此射手“射击一次命中环数≥7”的概率为______.
【答案】0.88
【解析】根据射手射击所得的环数ξ的分布列，有P(ξ=7)＝0.09，P(ξ=8)＝0.28，P(ξ=9)＝0.29，P(ξ=10)＝0.22，所求的概率P(ξ≥7)＝0.09+0.28+0.29+0.22＝0.88.
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根据短文内容，用方框中所给词的适当形式填空，有一个多余选项
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Last week my parents and I went to a(n) 【1】 ，which was about natural disaster. The speaker talked about many natural disasters such as earthquakes, floods tsunamis and volcanic 【2】 . All these can do much 【3】 to the plants and animals and of course, at the same time have a great 【4】 on people’s life.He told us it is important to have some basic knowledge in order to 【】 ourselves from being killed if some day a disaster really happens. Yes. I think the Chinese will never forget May 12,2008, when the terrible earthquake hit Wenchuan County, 【6】 many houses,schools, factories and roads. Many people were【7】 alive. The earthquake left thousands of people homeless. 【8】 , help, such as money, food,clothes, medicine and tents, came from every corner of the world. Some people, though not rich, still donated a(n) 【9】 amount of money to the earthquake-striken areas. The soldiers kept 【10】 day and night for the possible survivors from the ruins.We are deeply moved by all these, and I fully understand-One in need,help from all the directions.