1.某位老师想了解班上60名同学中，约有多少比率在国中前即谈过恋爱，於是他设计了 A、B两份问卷(其中A卷40张，B卷20张)以及不记答案卷60张随机发给班上同学(同学 不是拿到A卷就是B卷.至於A、B卷皆不回收，但答案卷要回收)，其中A卷的问题是「 我曾经在国中以前谈过恋爱」，因此拿到A卷的同学若国中前谈过恋爱就要在答案卷 上划O，若不曾谈过恋爱则划X；反之，B卷的问题是「我不曾在国中以前谈过恋爱」， 因此拿到B卷的同学若国中前谈过恋爱，就要在答案卷上划X，若不曾谈过恋爱，则划O， 如此设计，不论某位学生回答的结果是O或X，老师都无法得知该生在国中以前是否谈过 恋爱，但却可大致了解全班状况。答案卷经回收後，老师发现60张答案中友25张划O， 35张划X。请求出在本班同学中，约有多少比率的同学曾在国中以前谈过恋爱? 2.A city has professional basketball team playing at home and professional hockey team playing away on the same night. According to probabilities for professional sports published in Chance (Fall, 1992), a professional basketball team has a 0.641 probability of winning a home game, and a profess ional hockey team has a 0.462 probability of winning an away game. Historically,when both teams play on the same night, the chance that the next morning's leading sports story will be about the basketball game is 60% and the chance that it will be about the hockey game is 40%. Suppose that on the morning after these games the newspapers' leading sports story begins with headline “We Win!!” What is the probability that the story is about the basketball team? 先谢谢大家帮忙解惑喔 --

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