在异方差条件下普通最小二乘法具有如下性质()A.线性 B.无偏性 C.最小方差性 D

题型:多项选择题

问题:

在异方差条件下普通最小二乘法具有如下性质()

A.线性

B.无偏性

C.最小方差性

D.精确性

E.有效性

考点:经济学计量经济学计量经济学题库
题型:多项选择题

如图所示,红蜡块能在玻璃管的水中匀速上升,若红蜡块在A点匀速上升的同时,使玻璃管水平向右做匀加速直线运动,则红蜡块实际运动的轨迹是图中的(    )

A.直线P

B.曲线Q

C.曲线R

D.无法确定

题型:多项选择题

物体做匀速直线运动,有一对大小为25N的平衡力加在这个物体上,该物体的运动状态将______.(改变或不改变)

题型:多项选择题

读写任务 (共1小题,满分25分)

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。

Hi, I am Mike. I just went through my first year of college. The toughest part on me at fir

st was the general adjustment.1 went to a very small high school where my mom was a teacher and she did practically everything for me. But at the college I needed to know some basic life skills. such as balancing a check—book, laundry, and the things you have to be able to handle that I never thought of in the high school! It was really tough for me at first and I got badly homesick.

Once that first semester was over and I got used to the college life, I loved it—good facilities, helpful instructors. and a good library. The Students’ Union organizes various parties every week. I also go to cinemas and concerts, and often spend Saturday nights in pubs and clubs.

One thing I think is important is to get yourself active in things. I was on the dance team in college and met a ton of people that way ··· it was so much easier to make friends when you had a common ground.

[写作内容]

学校最近组织了一次中美学生交流活动,你参加其中的“大学校园生活”讨论。听完Mike的发言之后,你准备写一份发言稿,题目是“Preparing Myself for College Life”,内容要点包括:

1. 以约30个词概括Mike的发言要点;

2. 然后以约120个词谈谈你理想的大学生活,内容包括:

(1) 对中学生活的感受;

(2) 理想的大学生活;

(3) 中学生活和大学生活的差别,以及你打算如何适应。

[写作要求]

1. 在作文中可以使用自己亲身的经历或虚构的故事,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;

2. 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,篇章连贯。

题型:多项选择题

下列各项人粪尿的无害化处理的措施中,不科学的是(  )

A.兴建生态厕所

B.高温堆肥

C.建沼气池

D.加水稀释

题型:多项选择题

正常硫酸钡吸附血浆中含有的主要凝血因子为()

A.因子Ⅰ、Ⅴ、Ⅷ、Ⅺ、Ⅻ

B.因子Ⅸ、Ⅹ、Ⅺ、Ⅻ

C.因子Ⅱ、Ⅶ、Ⅹ

D.因子Ⅶ、Ⅹ

E.因子Ⅺ、Ⅻ

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