题目

The film Goodbye Mr Loser(《夏洛特烦恼》)has neither a team of shining stars nor a money-consuming publicity campaign to appeal to numerous moviegoers. But __61__ it does have is a bunch of middle-aged actors and actresses pretending to be high school students. Yet _62_ is amazing that the film is funny enough to earn it belly laughs from beginning to end. The movie, just __63_ the title indicates, is about a small fry named Xia Luo, who is merely _64_ loser. He’s down and out with no job, and he lives with his wife in a crowded apartment .In a dream, Xia relives his life with7．假设某种设备使用的年限x（年）与所支出的维修费用y（元）有以下统计资料：使用年限x23456维修费用y24567若由资料知y对x呈线性相关关系．试求：（1）求$\overline x，\overline y$；（2）线性回归方程$\hat y=\hat bx+\hat a$；（3）估计使用10年时，维修费用是多少？（参考公式：$\hat b=\frac{{\sum_{i=1}^n{（{x_i}}-\bar x）（{y_i}-\bar y）}}{{\sum_{i=1}^n{{{（{x_i}-\bar x）}^2}}}}=\frac{{\sum_{i=1}^n{{x_i}{y_i}}-n\bar x\bar y}}{{\sum_{i=1}^n{{x_i}^2-n{{\bar x}^2}}}}$，$\hat a=\bar y-\hat b\bar x$）