问题 选择题

分层抽样又称类型抽样,即将相似的个体归入一层,然后每层抽取若干个构成样本,分层抽样为保证每个个体等可能入样,必须进行  [ ]

A.每层等可能抽样

B.每层不等可能抽样

C.所有层用同一抽样比,每层等可能抽样

D.所有层抽取同样的样本容量,每层等可能抽样

答案

答案:C

单项选择题
阅读理解

There are four forms about medicine. Every must know how to use the medicine. Because it is very important. Never take any by mistake.

1)Take the medicine with water, followed by one tablet every eight hours as required. For further night-time and early morning, take two tablets at bedtime. Do not take more than six tablets in 24 hours. For Children six to twelve years old, go to your doctor for advice. Reduce dosage(剂量) if nervousness, restlessness or sleeplessness takes place.

2)Each pill of the medicine taken three times every day for fourteen years old. As usual, a pill 6:00 a. m. before breakfast, one before 11:00 and one before sleep. Not for children under six years old and old persons with heart attack.

3)The medicine for a person with a fever. Once two pills a day before sleep for adult. Not take the medicine without fever. Half for Children under 12 years old. Children with a high fever go to see a doctor.

4)The medicine taken three times a day. Once five pills for adult with a cold. Half of the pills for children 10 years old. Take the medicine before breakfast, lunch, supper or before sleep.

小题1:Obviously a kind of medicine can’t be proper for____judging from the information.        

A.some old persons with heart attack

B.some old persons with a fever

C.children over twelve years old

D.neither adults nor heart attack小题2:When a person has a cold. he had better      .

A.have twice a day

B.have about more than fourteen pills a day

C.have four times a day

D.have nine pills a day小题3:How many kinds of medicine are used for the children six years old?

A.All of them.

B.Three kinds of medicine.

C.Two kinds of medicine.

D.Almost not any medicine.