在线性回归模型中,随机误差μ被假定服从()A、正态分布 B、二项分布 C、指数分布 D、t

题型:单项选择题

问题:

在线性回归模型中,随机误差μ被假定服从()

A、正态分布

B、二项分布

C、指数分布

D、t分布

考点:统计学统计学综合练习统计学综合练习题库
题型:单项选择题

能正确表示下列反应的离子方程式是(  )

A.含等物质的量的硫酸氢铵与氢氧化钾两种溶液混合:NH4++HSO4-+2OH-=SO42-+NH3↑+2H2O

B.苯酚与碳酸钠溶液反应:2C6H5OH+CO32-=2C6H5O-+CO2↑+H2O

C.在稀氨水中通入过量CO2:NH3•H2O+CO2=NH4++HCO3-

D.Fe(NO33溶液中加入过量的HI溶液:2Fe3++2I-=Fe2++I2

题型:单项选择题

下面哪个指标能够比较准确便捷地说明人口增长的速度?[ ]

A.出生率

B.死亡率

C.人口自然增长率

D.人口密度

题型:单项选择题

阅读下面的短文,然后按照要求写一篇150词左右的英语短文。

There is a growing debate about the most effective way for students to study.  Traditionally studying alone was thought to be the best way to ensure good exam results. When studying alone, you can focus your mind better than when you are with others. You also have the freedom to choose what topic to study and when, as you don't need file agreement of others. Students that prefer to study alone often say that when they study with their classmates they waste a lot of time because the discussion is often about non-study topics such as television or holidays.

In the last few years, however, more and more students have started studying in groups. There are several reasons many students prefer this method. First, they find that studying in groups is more fun as they can share the experience with others rather than staying in their rooms. In groups, they can discuss the subject together and when something is not understood they can ask each other questions. They can use the knowledge of their classmates to help improve their own knowledge.  Finally by discussing the topic they are able to both understand and remember it better.

[写作内容]    

(1) 以约30个词概括短文的要点;

(2) 然后以约120个词就“独自学习好还是与他人合作学习好”的主题发表看法,并包括如下要点:

① 你喜欢独自学习还是与他人合作学习;

② 根据你个人的学习经历,简述你的理由;

③ 你的老师对你的学习方式的看法和建议;

④ 你认为怎样的学习方式才能取得最佳的学习效果。

[写作要求]  

1. 标题: The Best Way to Learn

2. 可以使用实例或其他论述方法支持你的论点,也可以参照阅读材料的内容,但不得        直接引用原文中的句子;

3. 作文中不能出现真实姓名和学校名称。

[评分标准] 概括准确,语言规范,内容合适,语篇连贯。

题型:单项选择题

哪种情况不得以低于成本的价格销售医药商品()

A.处理积压医药商品

B.清偿债务

C.与对手竞争

D.转产

E.歇业

题型:单项选择题

入侵攻击都是要收费的,因此脚本很难获得()

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