已知总体服从正态分布,且总体标准差σ,从总体中抽取样本容量为n的产品,测得其样本均值

题型:单项选择题

问题:

已知总体服从正态分布,且总体标准差σ,从总体中抽取样本容量为n的产品,测得其样本均值为 ,在置信水平为1-α=95%下,总体均值的置信区间为()。

A.A

B.B

C.C

D.D

考点:初级统计师统计方法统计方法题库
题型:单项选择题

阅读理解。

    Almost every day, we discuss the topic of health, especially for kids. But what is health? "Health" means

eating well, getting enough exercise, and having a healthy weight. Let's read the following rules. They can

help you stay healthy.

   1. Eat a variety of foods, especially fruit and vegetables. We all know that eating fruit and vegetables can

help us stay healthy, but many of us only eat our favorite foods. Remember that we can only get the

nutrition (营养) we need by eating different kinds of food, especially fruit and vegetables. 

   2. Drink water and milk most often. Everyone knows that water is important. Besides that, kids need plenty

of calcium (钙) to grow strong bones, and milk has a lot of it. Every day, you should drink at least three cups

of milk(1300 milligrams of calcium), when you are 9 years old or older. You should also try to have less

sugary drinks, like soda and coca. They include a lot of sugar. Sugar just includes calories, not important

nutrition.

   3. Listen to your body. When you are eating, notice how your body feels. When your stomach feels

comfortably full, stop eating. Eating too much makes you feel uncomfortable. If you do it too often, it can

make you unhealthy and fat.

   4. Limit (限制) screen time. What's screen time? It's the amount of time you spend watching TV, movies,

and playing computer games. The more time you spend on these sitting-down activities, the less time you

spend playing sports, like basketball, and doing other activities like bike riding and swimming. Try to spend

no more than 2 hours a day on screen time.

1. In this passage, "health" includes all of the following EXCEPT (除了) ______. [ ]

A. eating well

B. doing more exercise

C. having a healthy weight

D. wearing comfortably

2. The underlined phrase "a variety of" means ______. [ ]

A. lots of   

B. all kinds of   

C. the rest of   

D. a lot of

3. Which of the following is NOT true? [ ]

A. Eating more fruit and vegetables is difficult for some people.

B. We should eat and drink something with less sugar.

C. When we are full, we should stop eating, however (不管怎样) delicious the food is.

D. We should spend the same time on both sitting-down activities and on sports.

4. As kids, we should drink at least ______ to grow strong bones. [ ]

A. four cups of milk

B. three cups of milk

C. two cups of milk

D. one cup of milk

5. What's the main idea of the passage? [ ]

A. How to eat healthily.

B. Eating and playing are both important.

C. Advice for staying healthy.   

D. Health is very important.

题型:单项选择题

口咽部恶性肿瘤的生物学特点包括:①具有沿软腭及咽侧壁黏膜向周围生长和向深层浸润的特性,其局部浸润性病灶多较广泛;②口咽部的淋巴组织和淋巴管丰富;③颈淋巴结转移高达50%~85%,若原发肿瘤已越过中线,其对侧淋巴结发生转移的概率为20%~30%。因此照射范围应该较大,但不包括()。

A.原发灶

B.咽淋巴环(韦氏环)

C.颌下区(ⅠB区)

D.颈深上(Ⅱ区)

E.颅底

题型:单项选择题

间停呼吸(Biots)见于()。

A.颅内压增高

B.支气管哮喘

C.胸部严重外伤

D.抑郁症

E.胸膜炎

题型:单项选择题

影响销售渠道选择的因素有( )。

A.产品因素

B.市场因素

C.企业因素

D.国家法律约束

E.中间商的特性

题型:单项选择题

电信业一般认为宽带骨干网的数据传输率达到

A.10Mbps

B.100Mbps

C.2Gbps

D.10Gbps

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