tania的考试复习计划贴：谢谢大家的帮助和支持！！M51,V41,760!

tania

以下是引用vacationer在2005-9-15 3:18:00的发言：

谢谢爱情海mm!

大概明白了. 那方差和标准差有什么不同呢? 都是怎么得来的?

不要笑我问的问题白痴啊

方差等于标准差的平方，方差＝每一项与均值的差的平方再求和,最后除以项的个数＝求和（Xi-X')^2/n，公式不好打，不知你明不明白，注意是先平方，再求和，最后除以个数

标准差就是把上面这个公式再开方就是了。

tania

以下是引用vacationer在2005-9-15 3:22:00的发言：

16: In recent years, networks of fiber-optic cable have been replacing electrical wire for transmitting telecommunications signals. Signals running through fiber-optic cables deteriorate, and so the signals must be run through a piece of equipment called a regenerator before being transmitted father. Light-Line is the leading manufacturer of signal regenerators. Therefore, Light-line is one of the companies that will most benefit if new long-distance fiber-optic telecommunications networks are constructed.

Which of the following, if true, casts the most doubt on the prediction about light-ling’s prospects?

A: Telecommunications signals sent along electrical wires can travel much farther than signals transmitted through fiber-optic before needing to be regenerated.

B: Expanding its production of regenerators will require Light-line to spend proportionately more on labor and materials.

C: The volume of signals that a fiber-optic cable can carry is several thousand times greater than the volume that can be carried by an electrical wire of similar size.

D: There are technologies that enable telecommunications signals to be transmitted without either wire or fiber-optic cable.

E: Several manufacturers are developing regenerator technologies that will allow signals to be transmitted many times farther than at present before requiring regeneration.

28: Rock samples taken from the remains of an asteroid about twice the size of the 6-nuke-wide asteroid that eradicated the dinosaurs has been dated to be 3.47 billion years old and thus is evidence of the earliest known asteroid impact on Earth.

A: has been dated to be 3.47 billion years old and thus is

B: has been dated at 3.47 billion years old and thus

C: have been dated to be 3.47billion years old and thus are

D: have been dated as being 3.47 billion years old and thus

E: have been dated at 3.47 billion years old and thus are

这两题你们都达成共识了,可是我不明白

16题，原文推理为fiber-optic telecommunications networks deteriorate signals－>需要regenerator ，又因为Light-Line is the leading manufacturer of signal regenerators－》Light-line will most benefit 。题目要求削弱。E选项说明制造商正在发明一种新的技术，它使信号比原来regenaration之前能传输更远的距离，所以网络的建设不需要那么多的regenarator 了，削弱了公司获利的结论。

第18题，我是看了讨论帖，上面3w举了og使用date at 的用法，与这里一样，所以我同意E正确。但具体是哪个例子，我不记得了，回头找到了再给你贴上来

vacationer

刚才总结GWD的CR,发现这道没有答案,真奇怪.

GWD-9-Q13:

Fact: Asthma, a bronchial condition, is much less common ailment than hay fever, an allergic inflammation of the nasal passages.

Fact: over 95 percent of people who have asthma also suffer from hay fever.

If the information given as facts above is true, which of the following must also be true?

1. Hay fever is a prerequisite for the development of asthma



2. Asthma is a prerequisite for the development of hay fever



3. Those who have neither hay fever nor asthma comprise less than 5 percent of the total population



4. The number of people who have both of these ailments is greater than the number of people who have only one of them



5. The percentage of people suffering from hay fever who also have asthma is lower than 95 percent.

vacationer

以下是引用tania在2005-9-15 8:37:00的发言：


经查，reduce和rate的用法只能是reduce the rate，所以这里应该是rate be reduced 的用法，C之所以不对，是因为其中的it不清楚，it 不可以指代A's B中的A，而且A选项中的三个部分完美平行对称，后面两项都省略了第一项中的could be，所以应该选A。

啊,我明白了,又是代词指代问题

那A怎么不是 be better enforced, and its crime rate be reduced 呢? 这个be为什么要省略?

vacationer

以下是引用tania在2005-9-15 8:43:00的发言：

方差等于标准差的平方，方差＝每一项与均值的差的平方再求和,最后除以项的个数＝求和（Xi-X')^2/n，公式不好打，不知你明不明白，注意是先平方，再求和，最后除以个数

标准差就是把上面这个公式再开方就是了。

恩,明白了,谢谢tania

方差的英文是deviation? 标准差是standard deviation? 不过这个公式好像跟我问的那道没什么关系啊

vacationer

以下是引用tania在2005-9-15 8:54:00的发言：

16题，原文推理为fiber-optic telecommunications networks deteriorate signals－>需要regenerator ，又因为Light-Line is the leading manufacturer of signal regenerators－》Light-line will most benefit 。题目要求削弱。E选项说明制造商正在发明一种新的技术，它使信号比原来regenaration之前能传输更远的距离，所以网络的建设不需要那么多的regenarator 了，削弱了公司获利的结论。

第18题，我是看了讨论帖，上面3w举了og使用date at 的用法，与这里一样，所以我同意E正确。但具体是哪个例子，我不记得了，回头找到了再给你贴上来

那么D说有新技术可以不用wire也不用cable来传输信号,不是也可以避免这个问题吗?

18题既然og上有例子,那就没话说了,等着你贴上来.

vacationer

GWD-10-Q30:GWD-2-17

The quality of unrefined olive oil is not actually defined in terms of acidity, yet extensive tests have shown that the less free oleic acid an unrefined olive oil contains per liter, the higher its quality.  The proportion of free oleic acid that an olive oil contains is an accurate measure of the oil’s acidity.

If the statements above are all true, which of the following conclusions is best supported by them?

1. When an olive oil is refined, the concentration of oleic acid in the oil is reduced.
   



2. The quality of an unrefined olive oil can be determined only by accurately measuring its acidity.
   



3. If an unrefined olive oil is intermediate in acidity between two other unrefined olive oils, it will also be intermediate between them in quality.
   



4. Free oleic acid is the only acid that unrefined olive oil contains.
   



5. People who judge the quality of unrefined olive oils actually judge those oils by their acidity, which the judges can taste.

这一题有结论了吗?

我觉得C跟第1句话矛盾,但是刚才看讨论贴,tania说A中oleic acid跟文中free oleic acid不一样,真是痛苦

[此贴子已经被作者于2005-9-15 10:32:56编辑过]

tania

以下是引用vacationer在2005-9-15 9:25:00的发言：

啊,我明白了,又是代词指代问题

那A怎么不是 be better enforced, and its crime rate be reduced 呢? 这个be为什么要省略?

对不起，早上心情太好，没认真看，应该是选B，后两项都省略了could be

tania

以下是引用vacationer在2005-9-15 9:41:00的发言：

那么D说有新技术可以不用wire也不用cable来传输信号,不是也可以避免这个问题吗?

18题既然og上有例子,那就没话说了,等着你贴上来.

原文说啦：Therefore, Light-line is one of the companies that will most benefit if new long-distance fiber-optic telecommunications networks are constructed.

这是原文的前提，D选项否定了这个前提，是错误的

wwwhahchn

以下是引用tania在2005-9-15 11:22:00的发言：


对不起，早上心情太好，没认真看，应该是选B，后两项都省略了could be

tania有什么好事这么高兴？？