相对数使用时要注意以下几点,其中哪项是不正确的()。 A.比较时应做假设检验 B.要

题型:单项选择题

问题:

相对数使用时要注意以下几点,其中哪项是不正确的()。

A.比较时应做假设检验

B.要分清离散程度和变异程度

C.不要把构成比当率分析

D.二者之间的可比性

E.分母不宜过小

考点:全科医学(医学高级)医学统计方法医学统计方法题库
题型:单项选择题

If you usually take the school bus or sometimes need to take public buses to school, there are some important rules you should know.

·When you are waiting for the bus, you should wait at the bus stop, and stand well back.

·When you get off the bus, make sure you and the driver can see each other, and wait for the driver to signal you before you cross the road in front of the bus.

·Never go back for anything you may leave on the bus when it is starting.

·Never bend down near the bus when you walk to or from the bus stop.

·You should cross the street at a crosswalk or a street corner, and wait for the light to turn green or for the WALK crossing signal.

·It is important to look carefully to the left, the right and the left again when you cross the street.

·Remember that it is dangerous to stay in the areas around buses where the driver can’t see you. Don’t run between parked cars or buses.

·Do not run across the street or through parking areas to catch up with your friends.

小题1:When you are waiting for the bus, you should wait   .

A.at the bus stop

B.on the street

C.at a crosswalk

D.a street corner小题2:It is important to     when you cross the street.

A.run quickly     

B.wait for the light to turn green

C.look carefully to the left

D.look carefully to the right小题3:If you walk to or from the bus stop, you mustn’t        .

A.bend down on the bus

B.cross the street at a crosswalk or a street corner

C.bend down near the bus

D.look carefully to the left, the right and the left again小题4:This passage is mainly about       .

A.safety rules for students by bus

B.safety rules for drivers

C.safety rules for children by train

D.how to cross the street

题型:单项选择题

鸟类的受精方式属于体内受精.______.

题型:单项选择题

根据《中华人民共和国防沙治沙法》,在沙化土地范围内从事开发建设活动的,必须事先就该项目可能对当地及相关地区生态产生的影响进行()。

A.预期评估

B.环境规划

C.生态影响评价

D.环境影响评价

题型:单项选择题

肺结核

A.胸片大片致密影呈肺叶或肺段分布
B.胸片大片状阴影内有空洞、液平
C.胸片有空洞形成,壁较厚,内壁凹凸不平
D.两肺纹理增强呈卷发样阴影
E.有空洞形成,同侧或对侧有小片状条索状阴影

题型:单项选择题

不会造成催化蒸馏塔压力超高的是()。

A、回流量高即回流比过大

B、塔顶冷凝器堵塞

C、进料中异丁烯含量高

D、塔釜加热蒸汽量大

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