题目

 为了解某班学生喜爱打篮球是否与性别有关，对本班50人进行了问卷调查得到了如下的列联表：喜爱打篮球不喜爱打篮球合计 男生20525 女生101525 合计302050 （1）用分层抽样的方法在喜欢打蓝球的学生中抽６人，其中男生抽多少人？ （2）在上述抽取的６人中选２人，求恰有一名女生的概率. 答案： 解:（1）4（2）  解析 ：解：（1）在喜欢打蓝球的学生中抽６人，则抽取比例为 ∴男生应该抽取人  …………………………４分 （2）在上述抽取的6名学生中, 女生的有2人，男生4人。女生2人记；男生4人为， 则从6名学生任取2名的所有情况为:、、、、、、、、、、、、、、共15种情况，……………… Do you know the story about Vince? It was a true story. Vince was an English boy and he was eight years old. He didn't like soap or water. Three or four times a day his mother said to him, “Vince, your hands are very dirty again.Go and wash them. ” But Vince never washed them well. He only put his hands in the water for a few seconds and then took them out again.Vince’s uncle and aunt lived in another city. One day they came to stay with Vince’s parents, and they brought their small son, Toby, with them. Toby was seven years old and he didn’t like soap or water, ei­ther.The boys sat with their parents for a few minutes and then they went outside. When they were playing, Vince looked at Toby's hands and then went back to Toby’s parents and said proudly (骄傲地）， “Toby’s hands are dirtier than mine, ”“Of course they are，”Toby said angrily. “You are one year older than I am, ”1. Vince’s mother asked him to______ three or four times a day.A. wash his hands B. do his homework C. clean his bedroom2.When Vince saw Toby’s hands, he felt________.A, sorry B. proud C. sad3. Vince’s hands were a little______ than Toby’s.A. dirtier B. cleaner C. bigger4.From the story we know that_______.A. Vince liked soap and water, but Toby didn’tB. Toby liked soap and water，but Vince didn’tC. Vince and Toby didn’t like soap or water5. How many people are there in the story?A. Four. B. Five. C. Six