已知在一个样本中有50个数据,它们分别落在5个组内,第一、二、三、四、五组数据的

题型:填空题

问题:

已知在一个样本中有50个数据,它们分别落在5个组内,第一、二、三、四、五组数据的个数分别为2,8,15,x,5,则x等于______,第四组的频率为______.

考点:频数与频率
题型:填空题

阅读下面短文和问题,根据短文内容和每小题后的具体要求,在答题纸相应题号后的横线上写下相关信息,完成对该问题的回答。答语要意思清楚,结构正确,书写工整。

When the Nintendo Wii went on sale, people around the country stood in line for hours to get one. The popular video-game system isn’t just for fun and games. People such as Billy Perry, 64, are using Wii games to recover from pain and injuries. Perry plays Wii boxing and he says the game is helping him regain strength and feeling in his left arm. It is actually helping him recover from a stroke he had last year. A stroke is the sudden loss of consciousness and voluntary movement caused by a blocked artery (受阻碍的动脉)in the brain.

Across the country, hospitals are having patients try their hands at the Nintendo Wii. Playing the games can improve a patient’s strength and coordination (协调能力). It is especially useful for people who are trying to recover from strokes and broken bones. The Wii console (控制台)has a unique wireless controller. The controller requires players to move their bodies to play Wii games such as tennis, golf and baseball. Experts say the arm and hand movements Wii players make are similar to traditional exercises performed in physical therapy (treatment).

Physical therapy is often painful. Some medical experts say playing games on the Wii takes patients’ attention away while giving them the exercise they need. Walter Reed Army Medical Center in Washington D.C., offers Wii games for soldiers injured in the war. Doctor Daugherty says the practice is great for young soldiers who are interested in video games. “They think it’s for entertainment, but we know it’s for therapy. ”she says. Some experts want more proof that the Nintendo Wii helps the injured recover. Researchers in Minneapolis are doing a study to measure patients’ functions before and after using a Wii.

按具体要求回答下面问题,在答题纸相应题号后的横线上写下相关信息。

小题1:What is the Nintendo Wii? (不多于4个词)

小题2:Who might be able to benefit most from Wii games? (不多于8个词)

小题3:Why isn’t playing Wii games so painful as physical therapy? (不多于6个词)

小题4:What is the main idea of the whole passage? (不多于7个词)

题型:填空题

欧洲人口数量属世界各大洲的第几位?[ ]

A、第三位

B、第五位

C、第六位

D、第二位

题型:填空题

(4分)用符号完成下列内容:

(1)一种常见的单质_____________;      (2) 一种常见的化合物_____________;

(3) 一种常见的有机物_____________;   (4) 一种常见混合物的主要成分_________.

题型:填空题

菱苦土地面一般由苛性菱镁矿、锯末和氧化镁水溶液组成。( )

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在投资偏差分析时,需对偏差产生的原因进行分析,其中材料涨价属于( )。

A.客观原因
B.业主原因
C.设计原因
D.施工原因

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