2008 First Semester STATS课程官方问答贴

t-multiplier

原帖由 雨轩听风 于 2008-3-30 11:47 发表



我想问一下..这个题目是问based on this data, do you agree with the sociology student's conclusions that the admissions criteria were biased against females?

那不是应该看 IP(A|F&L)等于不等 ...

Hi there, yep, that's my understanding of the question.

弥漫记忆

请教STATS10X的

assignment1
question5
(f) By hand, draw side-by-side dot plots of the word lengths for the two novels.

如果想用excel该怎么办呢？？？

谢谢

弥漫记忆

想一起打印出来，所以。。。。

流产的处女

麻烦楼主我还想请问下。 STATS 10X ASS1

QUESTION。5

如果我画DOT PLOTS的时候 还可以看出一点趋势。 画成X点图了以后咋就什么趋势也看不出来了呢？
这种情况合理吗？
Overall, the distribution of the word lengths seems to be roughly symmetric and unimodal for the two books. The means, medians is very close but spread is symmetry. Schindler’s List has a outlier in the upper side, it is Right skew longer upper tail. Hotel de Dream has a outlier in the lower side, it is Left skew longer lower tail.

z-score

原帖由 雨宁 于 2008-3-30 20:34 发表



题目说用手画不是吗？
为什么还要用ＥＸＣＥＬ呢？

不好意思，只能用手画。

z-score

原帖由 流产的处女 于 2008-3-30 21:10 发表
麻烦楼主我还想请问下。 STATS 10X ASS1

QUESTION。5

如果我画DOT PLOTS的时候 还可以看出一点趋势。 画成X点图了以后咋就什么趋势也看不出来了呢？
这种情况合理吗？http://byfiles.storage.live.com/ ...

我说说我怎么看这幅图的:

The mean for Schindler's List seems to be slightly higher than that for Hotel de Dream. Schindler's List seems to be slightly more variable than Hotel de Dream. Both novels have a single outlying value.

z-score

原帖由 雨轩听风 于 2008-3-30 14:41 发表
你说的是:"如果admission policies are fair, then IP(A|F&L)=IP(A|F&L`), IP(A|F`&L)=IP(A|F`&L`). "

但是我为什么觉得应该看 IP(A|F&L)等于不等于IP(A|F`&L) 和你说的IP(A|F&L)=IP(A|F&L`)不同年呢
和IP( ...

等等啊，我再去看看。

流产的处女

原帖由 z-score 于 2008-3-30 21:20 发表


我说说我怎么看这幅图的:

The mean for Schindler's List seems to be slightly higher than that for Hotel de Dream. Schindler's List seems to be slightly more variable than Hotel de Dream. Bot ...

楼主是说这两本的DOT PLOTS吧？

那之前有贴过的那张只针对 HOTEL DE DREAM 的WORD LENGTH该怎么说明啊？

z-score

原帖由 流产的处女 于 2008-3-30 21:41 发表



楼主是说这两本的DOT PLOTS吧？

那之前有贴过的那张只针对 HOTEL DE DREAM 的WORD LENGTH该怎么说明啊？

那个图可以说There seems to be no apparent relationship between word length and number of words for Hotel de Dream.

z-score

恩，没问题。明天早上脑子清醒帮你看。星期二之前肯定没问题。

akl

An experiment, Get Going With Breakfast, was recently conducted to demonstrate the importance of eating breakfast to teenagers. One hundred and sixty pupils, from five different secondary schools throughout New Zealand, were given breakfast every day for the month of August. Changes in their energy levels and physical and mental performance at school were monitored. The classes were also involved in special mentoring sessions each week with some of New Zealand's top sports people.

Which one of the following statements is NOT a potential problem with this experiment?

A possible placebo effect was ignored.

The effect of the daily breakfast on academic performance may be confounded with the effect of the 'special mentoring sessions'.

There is no mention of the use of a control group.

There is no mention that some form of randomisation was used.

The sample size is too small compared with the total number of New Zealand teenagers.  
  


怎么答阿?谢谢了

z-score

原帖由 雨轩听风 于 2008-3-30 23:05 发表
周二due哦.麻烦你最迟明天告诉我啦..谢谢

刚才又看了一下，我觉得你说的那种比较和比较IP(A | F & L)和IP(A | F & L')然后比较IP(A | F' & L)和IP(A | F' & L')都是valid justifications. 因为每个比较都能得出新的结论。

感觉这样会是一个公平的比较，希望阿童木没有想得太幼稚。

[ 本帖最后由 z-score 于 2008-3-31 09:02 编辑 ]

z-score

原帖由 akl 于 2008-3-31 08:50 发表
An experiment, Get Going With Breakfast, was recently conducted to demonstrate the importance of eating breakfast to teenagers. One hundred and sixty pupils, from five different secondary schools ...

The sample size is too small compared with the total number of New Zealand teenagers.

这个是不是Cecil的问题啊？

akl

是啊!快点帮帮我啊 !

还有这个,我也不确定...
The National Certificate of Educational Achievement (NCEA) for New Zealand high school students is due to replace the School Certificate examinations in 2002. A Christchurch High School teacher recently sent a questionnaire to all high school teachers in New Zealand. His aim was to assess the reactions of teachers to the NCEA. One factor that may influence teachers' opinions is the decile rating of their school. The decile rating is a number form 1 to 10, where 10 is the highest, and it acts as a socioeconomic indicator. Approximately 12% of teachers from all New Zealand high schools responded to the questionnaire.

This investigation was designed to be:

an observational study.  
a blocked experiment.  
a sample survey.  
a pilot survey.  
a census.

akl

原帖由 akl 于 2008-3-31 08:50 发表
An experiment, Get Going With Breakfast, was recently conducted to demonstrate the importance of eating breakfast to teenagers. One hundred and sixty pupils, from five different secondary schools ...

题上问得是not a potential problem, 我怎么感觉像是
There is no mention that some form of randomisation was used.呢，哪不对？

z-score

原帖由 akl 于 2008-3-31 09:14 发表



题上问得是not a potential problem, 我怎么感觉像是
There is no mention that some form of randomisation was used.呢，哪不对？

There was no mention that some form of randomisation was used. 的确没有用randomisation, 所以不是Not a potential problem.

对不对？

z-score

原帖由 akl 于 2008-3-31 09:11 发表
是啊!快点帮帮我啊 !

还有这个,我也不确定...
The National Certificate of Educational Achievement (NCEA) for New Zealand high school students is due to replace the School Certificate examination ...

Sample survey. 不是吗？

akl

1

In December 2003 the University of Auckland Recreation Centre published the results of their Client Satisfaction Survey . The survey was a written questionnaire and available at the reception area to members of the Recreation Centre and casual visitors. 483 respondents answered question relating to the Recreation Centre. Which one of the following nonsampling errors is not a possible source of bias in the results of this poll?

Question effects Self-selection bias Interviewer effects Survey-format effects Behavioural considerations

2 Which one of the following statements is false?

For a large number of experimental units, random allocation of treatments leads to treatment groups that are roughly balanced with respect to unkown factors.  
An experiment involving human patients can involve pyschological effects. There should be an attempt to account for such effects in the design of the experiment.  
An observational study can alone be used to establish causation.  
In an experiment, the experimenter determines which experimental units receive which treatments.  
In an observational study, units that happen to have received different levels of a factor are compared.  



3 A study examined the effects of stress on the subsequent onset of diabetes. People living in stressful environments were selected and followed through to see if they developed diabetes. All instances of diabetes were recorded as they were diagnosed.
This type of study is best called:


a retrospective (case-control) study.  
a prospective study.  
a double-blind experiment  
a sample survey  
a controlled experiment  

神童木,帮我看看阿! 我答得对不对...

[ 本帖最后由 akl 于 2008-3-31 10:03 编辑 ]

akl

阿童木,快帮我看看啊!5555555555555555555555

akl

yeah, 全对了，谢谢 阿童木了，呵呵！！！！！！！！！！！！！！！1

akl

I am sure it's correct now, haha ,thanks anyway....

z-score

原帖由 akl 于 2008-3-31 09:27 发表
1 In December 2003 the University of Auckland Recreation Centre published the results of their Client Satisfaction Survey . The survey was a written questionnaire and available at the reception a ...

哦，sorry, 刚才我不在电脑前。

z-score

原帖由 akl 于 2008-3-31 10:09 发表
阿童木,快帮我看看啊!5555555555555555555555

哦耶，我们都是阿童木。祝贺你。