关于随机抽样,下列说法正确的是() A.随机抽样即随意抽取个体 B.研究者在随机抽样

题型:单项选择题

问题:

关于随机抽样,下列说法正确的是()

A.随机抽样即随意抽取个体

B.研究者在随机抽样时应精心挑选个体,以使样本更能代表总体

C.遵循随机化的原则从总体中抽取观察单位,使样本能较好地代表总体特征

D.为确保样本具有更好的代表性,样本量应越大越好

E.以上说法都不对

考点:儿童保健(医学高级)流行病学流行病学题库
题型:单项选择题

阅读理解。

     Are you the only child in the family? If so, you are the most important in your family. Parents are the

closest people to you in the world. But a lot of middle school students have a problem. They feel they're not

as close to their parents as before. They even don't think their parents are fair (公平的) to them.

     Some students complain that their parents often say a lot to them, but never listen to them. Some say their

parents don't allow them to play computer games when other classmates are doing that. Others say when

they're making phone calls to friends, their parents like to ask if they're speaking to a boy or a girl. These make

them very unhappy. Some students even decide to leave home because they're afraid to tell their parents when

they have done something wrong, especially when they do badly in exams. Then they usually think running

away is the only choice (选择). But they don't know running away may bring them some more problems.

     Problems are parts of life. Here are some suggestions for you to solve your problems.

    1) Find a good chance to talk with your parents. Don't be afraid to tell them your feelings.

    2)Get help from others like good friends or teachers.

    3)Keep a diary to help you understand more about yourself and your feelings.

    4)Show your parents you' re growing up. Then they'll feel you' re no longer a small child. If you follow

the advice, you'll have a happy life and never think of running away.

1. According to the article, ________ are the closest people to an only child.

A. teachers

B. classmates

C. parents

2. Which of the following is TRUE?

A. Parents don't love their children now.

B. Middle school students don't have any problems.

C. Some students don't think their parents are fair to them.

3. We'd better ________ if we have problems with them.

A. talk with our parents

B. quarrel with our parents

C. leave our parents

4. Why does the author advice us to keep a diary?

A. Because it's our homework.

B. Because it can help us practice writing.

C. Because it can help us understand ourselves better.

5. This article is about some middle school students' ________.

A. friends

B. hobbies

C. problems

题型:单项选择题

用科学记数法表示76000为______.

题型:单项选择题

德国经济学家、农业区位论的创始人冯·杜能,于1826年完成的《孤立国同农业和国民经济的关系》,成为世界上第一部关于()的古典名著。

A.区位理论

B.地租理论

C.新古典地租理论

D.地价理论

题型:单项选择题

加强中 * * 党对统一战线的领导,必须坚持()的方针。

A、荣辱与共

B、共同发展

C、互相监督

D、肝胆相照

E、长期共存

题型:单项选择题

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