抽样调查的特点包括() A.样本单位按随机原则抽取 B.会存在抽样误差 C.能够根据

题型:多项选择题

问题:

抽样调查的特点包括()

A.样本单位按随机原则抽取

B.会存在抽样误差

C.能够根据部分调查资料对总体的数量特征进行推断

D.是一种非全面调查

E.所有被调查单位都有一定的概率被抽取

考点:初级统计师统计方法统计方法题库
题型:多项选择题

现要验证“当合外力一定时,物体运动的加速度与其质量成反比”这一物理规律。给定的器材如下:一倾角可以调节的长斜面(如图所示)、小车、计时器、米尺、弹簧秤,还有钩码若干。实验步骤如下(不考虑摩擦力的影响,重力加速度为g),在空格中填入适当的公式。

(1)用弹簧秤测出小车的重力,除以重力加速度g得到小车的质量M;

(2)用弹簧秤沿斜面向上拉小车保持静止,测出此时的拉力F;

(3)让小车自斜面上方一固定点A1从静止开始下滑到斜面底端A2,记下所用的时间t,用米尺测量A1与A2之间的距离s,从运动学角度得小车的加速度a=__________;   

(4)已知A1与A2之间的距离s,小车的质量M,在小车中加钩码,所加钩码总质量为m,要保持小车与钩码的合外力F不变,应将A1相对于A2的高度调节为h=__________;   

(5)多次增加钩码,在小车与钩码的合外力保持不变的情况下,利用(1)、(2)和(3)的测量和计算结果,可得钩码总质量m与小车从A1到A2的时间t的关系式为m=__________。

题型:多项选择题

What is your favorite color? Do you like yellow, orange, or red? If you do, you must be an active person who enjoys life. Do you like blue? Then you are probably quiet, shy, and would rather follow than lead.

Colors do influence our moods (情绪). A yellow room makes most people feel more cheerful and more relaxed than a dark green one; and a red dress brings warmth and cheer to the saddest winter day. On the other hand, black is depressing(令人压抑的). There was a black bridge over the Thames River, near London. The number of people who killed themselves on that bridge used to be larger than on any other bridge in the area -- until it was repainted green.

Light and bright colors make people not only happier but also more active. In the factory, the workers will work better, harder, and have fewer accidents when their machines are painted orange rather than black.

小题1:An active person may like ____   

A.yellow, orange, or red

B.yellow, black, or red

C.orange, blue, or black

D.black, red, or orange小题2:Most people feel more __ in a yellow room than in a dark green one.

A.tired

B.bored

C.worried

D.relaxed小题3:More people killed themselves on the black bridge than on any other bridge probably because ____

A.the bridge was very tall

B.the bridge was too crowded

C.people didn't like the bridge

D.the color of the bridge was depressing小题4:In the factory, when the machines are painted orange, the workers will work __

A.worse

B.harder

C.more slowly

D.more angrily

题型:多项选择题

投注站三星级专营店面积最少要求为()平方米。

A、8

B、10

C、12

D、15

题型:多项选择题

水轮机主轴要同时承受()的综合作用

(A)压、扭及径向力

(B)拉、扭及径向力

(C)压、扭及轴向力

(D)拉、扭及轴向力

题型:多项选择题

成吉思汗的十世祖是()。

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