搜题请搜索小程序“爱下问搜题”
问题 单项选择题

在复相关分析中，为了排除其他变量的影响而单独反映两个变量之间相关关系的密切程度，需要计算（）。

A．简单相关系数

B．复相关系数

C．偏相关系数

D．回归系数

答案

参考答案：C

问答题 简答题

煤的硬度与煤层注水有何关系？
查看答案
单项选择题


It may be necessary, in order that .future (51) can enjoy clean air, that more of the (52) is borne by long-term central government fund．As air pollution varies enormously from place to place and can, indeed, be very local, it may also be necessary for the central government to (53) money so that local authorities can (54) special local problems. That these can be significant was shown by the report made in 1970 (55) behalf of the London Boroughs Association. This (56) that in central London since 1958 smoke concentrations have decreased by 80 percent, whereas sunshine has increased by 70 percent and winter visibility has (57) threefold, There have been (58) in mortality and hospital admissions (59) with air pollution and in the response to it of bronchitis, as well as clear if less documented increases in plant types and bird (60) n the cities.

A．associated

B．concerned

C．tied up

D．involved
查看答案