根据某水文观测点的历史统计数据，得到某河流水位X（单位：米）的频率分布直方图如图：将河流水位在以上6段的频率作为相应段的概率，并假设每年河流水位互不影响

（1）求未来三年，至多有1年河流水位X∈27，31）的概率（结果用分数表示）；

（2）该河流对沿河A企业影响如下：当X∈23，27）时，不会造成影响；当X∈27，31）时，损失10000元；当X∈31，35）时，损失60000元，为减少损失，现有种应对方案：

方案一：防御35米的最高水位，需要工程费用3800元；

方案二：防御不超过31米的水位，需要工程费用2000元；

方案三：不采取措施；

试比较哪种方案较好，并请说理由．

   It's the end of class. When the bell rings, students of Luohu ForeignLanguages School in Shenzhen quickly take out their cell phones.
They want to log on to their micro blogs to check the interesting things that have happened in the last hour.
   Since last year, the trend (潮流) of micro blogging has swept the country. Recent surveys shows that most students in middle schools have a micro blog and some even update their blogs over five times per day.
   "We learn many fresh and interesting things on micro blogs and they have become popular topics in class," said Andy Liang, 14. "If you do not know about them, you are out of the loop."
   It is also a great place for students to let out stress. "My parents always ask me to study hard, and encourage me before exams, but it really adds pressure," said Simon Zhang, 15. "When I share these feelings on my micro blog, I get many replies from friends in the same situation, which makes me feel better."
   But parents are worried that micro blogging could be a waste of time. Some misleading messages may even cause danger to kids, they said.
   Mr. Shen, a professor at the China Education Association, suggests parents not worry too much as long as kids are not crazy about micro blogging. Maybe it can become a window for parents to understand their children.
   "If parents can read their children's micro blogs, they'll know their thoughts, thus leading to better communication and solutions to problems," he said. He also gives some tips for kids.
   -Don't micro blog for more than one hour a day.
   -Never micro blog in class.
   -Try to talk face to face with people from time to time.
   -Be critical(批判性的). Don't trust all the messages on a micro blog.