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问题 单项选择题

最小二乘法的原理是，当所有的测量数据的( )最小时，所拟合的直线最优。

A．误差

B．偏差的积

C．误差的和

D．偏差的平方和

答案

参考答案：D

解析： 一元线性回归是工程中经常遇到的配直线的问题。通过试验，可以得到若干组的对应数据，根据这些数据画出相关图，当点大致分布在一条直线附近时，说明两变量之间存在线性关系，即可以用一条适当的直线来表示这两变量的关系。此直线方程为：y＝a+bx，a、b是回归系数，最小二乘法是根据偏差平方和最小的条件来选择常数a、b的方法，当所有数据偏差平方和最小时，所配的直线最优。

多项选择题

依据《道路交通安全法》的规定，有权对交通事故损害赔偿的争议进行处理的部门是( )。

A．人民法院

B．仲裁机关

C．公安机关交通管理部门

D．道路主管部门

E．人民调解委员会
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问答题

Campaigning for votes in the western province of Maharashtra this month, Prime Minister Manmohan Singh of India vowed to give such a remarkable facelift to Mumbai, the state capital, that people "should forget talking about Shanghai." Now that the election results are in, and a coalition led by Singh’s Congress Party has retained power in the province, the prime minister must make good his promise, which will take more than a paint job. The consulting firm McKinsey says it would cost $ 44 billion to make Mumbai a world-class city that can rank alongside Shanghai. A revival of Mumbai, the country’s trade and entertainment hub, is more than a matter of image. It’s an economic necessity. The city of 12 million fills two-fifths of the nation’s corporate-tax kitty, yet a third of its people live in slums. Mumbai’s economy has lagged the national average growth rate of about 7 percent since 1998 — a level of underperformance that is impossible to reverse without mending the city’s creaky infrastructure. A choked, potholed Mumbai is symptomatic of a wider urban malaise. It isn’t that a fast-growing economy like India can’t find the resources to invest in its cities, where much of its economic growth is being produced. By 2025, one of (the) two Indians would be living in an urban center, up from one in three now. Morgan Stanley’s chief economist, Stephen Roach, recently undertook a 115-mile, or 184-kilometer, car journey from Mumbai to the industrial city of Pune on a new expressway, which he says "is a huge cut above any of the other motor routes that I had been on in India." Yet, by Chinese standards, the new road merits a "B minus, at best," he says. "If this is progress in closing India’s infrastructure gap, the problem is even worse than I had imagined."
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