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问题 解答题
某机构为了研究人的脚的大小与身高之间的关系，随机测量了20人，得到如下数据：
身高（厘米）192164172177176159171166182166
脚长（码）48384043443740394639
身高（厘米）169178167174168179165170162170
脚长（码）43414043404438423941
（1）若“身高大于175厘米”的为“高个”，“身高小于等于175厘米”的为“非高个”；“脚长大于42码”的为“大脚”，“脚长小于等于42码”的为“非大脚”，请根据上表数据完成下面的2×2列联表．
（2）根据（1）中的2×2列联表，若按99%可靠性要求，能否认为脚的大小与身高之间有关系．
高个非高个合计
大脚
非大脚12
合计20
答案

（1）高个非高个合计
大脚527
非大脚11213
合计61420
（2）假设H°成立：脚的大小与身高之间没有关系

K2的观测值k2=

20(5×10-1×2)2
6×14×7×13
≈8.802

∵8.802＞6.635

∴我们有99%的把握认为脚的大小与身高之间有关系．

单项选择题 A1/A2型题

肺炎治疗有效时，症状检查顺序为（）

A.发热、咳嗽、WBC、胸片

B.发热、WBC、咳嗽、胸片

C.咳嗽、WBC、胸片、发热

D.WBC、发热、咳嗽、胸片

E.发热、咳嗽、胸片、WBC
查看答案
单项选择题

B


It keeps your insides from falling out. It helps you warm up when you are cold, and it can cool you off when you are hot. It lets you feel things by touch.
What is this Your skin, of course! What does your skin ask for in return for all the wonderful things it does Just a little care! So let’s learn how to take good care of our skin.
Like the heart and stomach, your skin is an organ(器官). In fact, it is the largest organ in your body. Unless there’s a problem, you may not think about your skin very much. But skin has an important job to do.
Your skin is protecting you. Your skin keeps you from getting sick. When you take care of your skin, you are helping your skin do its job. Taking care of your skin today will help you have no problems in the future.
Clean skin is happy skin! One simple way to take care of your skin is to keep it clean. Keeping your hands clean is very important. When washing your hands, use warm water. Wet your hands, and then use soap. You should wash your hands carefully everywhere.
You’ll also want to use warm water, but not too hot, when you take a bath. Use soap to clean your body. Don’t forget under your arms and behind your ears! Your face needs attention, too. It’s a good idea to wash your face once or twice a day with warm water.

Which of the following best describes your clean skin ( )

A．A kind of job to keep you from getting sick.

B．An important and largest organ.

C．Something like your heart and stomach.

D．Healthy and happy skin.
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