问题 选择题

要了解一批日光灯灯管的使用寿命,从中抽取了40个灯管进行实验。在这个问题中,40个灯管的使用寿命是

A.总体

B.个体

C.样本容量

D.总体的一个样本

答案

答案:D

分析:本题考查的是确定总体。解此类题需要注意“考查对象实际应是表示事物某一特征的数据,而非考查的事物”。我们在区分总体、个体、样本、样本容量这四个概念时,首先找出考查的对象,从而找出总体、个体,再根据被收集数据的这一部分对象找出样本,最后再根据样本确定出样本容量。

解答:本题中的总体是指这批日光灯管的全体的使用寿命,个体是指每只日光灯管的使用寿命,样本是指从中抽取的40只日光灯管的使用寿命,根据抽样调查的特征可知,40个灯管的使用寿命是总体的一个样本,故选D。

点评:本题考查的是确定总体、个体、样本。解此类题需要注意“考查对象实际应是表示事物某一特征的数据,而非考查的事物”。

判断题
阅读理解

阅读理解。

    It takes many years for you to grow up. There are two periods in your life when you grow rapidly. The

first period begins right after you are born and lasts until you are about six months old. The second period

starts when you reach the age of 13. First, girls grow faster than boys, then boys catch up and grow faster

and stronger.

    Your head stops growing earlier than the rest of you. By the time you are ten, your head is nearly full size.

The bones of your arms and legs are short when you are a baby. When you reach the age of nine, your bones

starts to grow rapidly, and will keep growing until you reach your full height (高度).

    Besides growing taller, your body changes in other ways. When a boy is about 13 years old, his voice begins

to get deeper and he may begin to grow a beard (胡子). At about the age of 13, a girl's body begins to function (运行) like a woman's. Some important changes are taking place, changes that makes it possible for boys and

girls, when they are older, to become fathers and mothers.

1. The first period in your life when you grow very rapidly ______. [ ]

A. lasts about thirteen years

B. lasts about six months

C. doesn't begin until you are about six months old

D. begins when you are six months old

2. Your head nearly stop growing ______. [ ]

A. when you are born

B. when you are ten years old

C. when you are thirteen years old

D. when you are six months old

3. About the age of 13, a child ______. [ ]

A. stops growing

B. reaching his full height

C. begins to grow a beard

D. begins to change in other ways

4. The meaning of the last sentence is that ______. [ ]

A. boys and girls are not sure to become fathers and mothers when they are old

B. it is necessary for boys and girls to become fathers and mothers when they grow up

C. boys and girls must have some important changes before they grow up

D. it is important that boys and girls should become fathers and mothers when they are older