2008 First Semester STATS课程官方问答贴

poison_ivy

341的问题...
a local surf life saving club wants to replace its 30 year old clubrooms which are dilapidated and too small for the number of club members and all the services the club provides.the club is located on a public reserve,right on the beach in the middle of a wealthy beach suburb.the local shopping centre,just 20 metres away down the road,is a busy local hub with a supermarket,a selection of shops and lots of cafes and restaurants.as part of the development the club management has suggested putting in a cafe.the local Council has suggested that before the club gets to far in planning or design of the new clubrooms,it should conduct some research to see what people think about the proposal for a new club--especially people who could be affected by a new larger club which is offering new services. the Council indicates that the results of theis research will be important in determining whether the Council will support the development of new larger clubrooms on public land.

the club managment ask for help in designing a survey of people who could be affected by the development of a new larger club.

偶只想到club members是一个populations of  interest.....还有哪些可以是populations of interest捏.....？

后面还问what could be use as sampling frame and how it would be used......
.....无知的某人完全晕了...|||||||||.....毫无概念....

请求搂主帮忙 谢谢~~

[ 本帖最后由 poison_ivy 于 2008-3-17 19:48 编辑 ]

ztswyz

> test.statistic <- (37.77-35)/(3.66/sqrt(25))
> 2*(1-pt(abs(test.statistic),25-1))
[1] 0.0009074216
>
不对啊 应该是
p-value=0.0008996
先不管第二题了 过几天答案下来了再问...
先问第一题

z-score

原帖由 ztswyz 于 2008-3-17 21:31 发表
> test.statistic  2*(1-pt(abs(test.statistic),25-1))
[1] 0.0009074216
>
不对啊 应该是
p-value=0.0008996
先不管第二题了 过几天答案下来了再问...
先问第一题

0.0009074216和0.0008996你看才差多少，我这个是拿R算的，你给的那个是不是用SPSS或Excel这种软件算得啊？不同软件算出来的P-value会不一样。

z-score

原帖由 303B25 于 2008-3-17 20:30 发表
Should be IP((W union P) given M)
that's what I think, not exactly sure though
are you in the 8am lecture?

原帖由 qian.qian 于 2008-3-17 20:15 发表
The cars without steering wheels fortunately have both windows and passenger seats present.

应该是IP(W and P given M)=0
还是IP((complement of W and P) given M)=1

应该是IP((W & P)` | M)=1.

To 303B25: I think she is right.

The cars without steering wheels fortunately have both windows and passenger seats present.

This is saying given the car is without a steering wheel, |W, the probability both (intersection) (P&W)`

z-score

原帖由 poison_ivy 于 2008-3-17 19:43 发表
341的问题...
a local surf life saving club wants to replace its 30 year old clubrooms which are dilapidated and too small for the number of club members and all the services the club provides.th ...

不好意思啊，341的问题好长，我先看完在解答。

水鱼皇后

原帖由 z-score 于 2008-3-17 10:29 发表




Thank you 303B25.

Addional to 303B25's response, this survey has a lot of non-response bias, like the people who can't understand English might refuse to do the interview completely.
...

谢谢303B25 & atm的回答
还有一个问题 也是这个题目的

After your comments, the Council decides to focus solely on cruise ship visitors. They
want to know what proportion of them visit the Cable Car and what they think of the
experience. What sampling frame could be used to generate a representative sample for
this survey and how would you use it?

这里的sampling frame是什么 我们不能access a list吧？
如果random sample cruise的乘客的话 这样算是sampling frame吗？

[ 本帖最后由 水鱼皇后 于 2008-3-17 22:46 编辑 ]

z-score

原帖由 水鱼皇后 于 2008-3-17 22:41 发表



谢谢303B25 & atm的回答
还有一个问题 也是这个题目的

After your comments, the Council decides to focus solely on cruise ship visitors. They
want to know what proportion of them visi ...

嗯，sampling frame for cruise ship visitors可以看为所有从Wellington港口下船的游客．你可以让工作人员在Wellington港口等待油轮靠港，randomly sample所有下船的游客们．

z-score

原帖由 poison_ivy 于 2008-3-17 19:43 发表
341的问题...
a local surf life saving club wants to replace its 30 year old clubrooms which are dilapidated and too small for the number of club members and all the services the club provides.th ...

Population of interest应该包括所有会受到new club room影响的人们．

The local shopping centre, just 20 metres away down the road, is a busylocal hub with a supermarket, a selection of shops and lots of cafes andrestaurants. As part of the development the club management hassuggested putting in a cafe.

population of interest(我想)应该是所有去超市，咖啡店和餐馆的人们．

sampling frame(我想)可以是在所有surrounding suburbs的人们．

z-score

原帖由 qian.qian 于 2008-3-18 11:37 发表
谢谢..阿童木...

"应该是IP((W & P)` | M)=1."
`是代表complement吧?

TO:303B25  
there is only one stream for stats210..

是的，complement.

chingk

i hv a question about 341 assn as well

A brewing company has an idea for a new range of “alco-pops”. These are flavoured alcoholic
drinks aimed at the youth (18 years +) market. One of the company’s marketing staff has
suggested that they do an on-line survey to find out what 18-20 year olds like about such drinks.
The marketing department asks your advice about the possibility of an on-line survey using
facebook, bebo or other ‘Web2.0’ sites. You advise them that adding a survey to such sites is
probably against the operational rules of those sites. You also offer them some general advice
about on-line surveys and suggest that there may be another way to do this survey using the
electoral roll as a sampling frame.

c) List the advantages and disadvantages of using the electoral roll for a sampling frame for
this study like this? [7 marks]


i can only think of 1 adv and 1 disadv for this question

for adv, we can ensure that all the people involve in our sample are aged 18+

and disadv could be not everyone in the population would be include in the electoral roll


so can u give me some hits about this question?

莫宁仔仔仔

看了半天，怎么一点326的都没有

莫宁仔仔仔

请教326的作业，谢谢先。

我图怎么就是做不出来呢！！妈呀~

高手帮我看看CODE 错那了？谢谢

> unemployment.ts<-read.table(file.choose(),header=T)
> attach(unemployment.ts)
> unemployment.ts
> unemployment.ts<-ts(unemployment,frequency=12,start=1956)
> plot(unemployment.ts,main="Canadian total unemployment figures (thousands) 1956-1975",xlab="year",ylab="unemployment figures(thousands)")

天外飞猪

请问。STATS108
第2题的那个survey。
A group of biologists is interested in surveying the abundance of barrel cactus in a particular desert. They divide the desert area up into 1200 equal sized rectangular areas. Of these, 247 areas are too difficult to access, so are excluded. Of the remaining 953 areas, 50 are chosen at random to be surveyed. The biologists then randomly select a 100 square metre section of each of these areas to survey. The number of barrel cacti in each of the chosen sections is then measured.

any sampling error over there?? i cannot get it .pls help me.

and also Q3.
(e) It was later suggested that gender could be a significant factor in Study 3. How could the study design be modified to take into account the gender effect?
我觉的原本的result不会因为性别的关系受影响，不用MODIFY。《--对么？？？那要怎么解释呢？？

(f) Which of the studies, if any, included a control group? For the studies that include one, briefly describe the control group.
STUDY3 NO ALCOHOL GROUP是CONTROL GROUP对么。。。第1各应该没有把。。还是NO ANY OFFERS' BAKERY是CONTROL GROUP？？！！

(h) Could the results of a study such as Study 2 be used to argue that any overall difference in the number of different jobs held is due to the degree studied? Briefly justify your answer.
不太理解她问的是什么
请阿童木解释下好么，。要怎样回答？？

谢谢

z-score

原帖由 莫宁仔仔仔 于 2008-3-18 17:14 发表
请教326的作业，谢谢先。

我图怎么就是做不出来呢！！妈呀~

高手帮我看看CODE 错那了？谢谢

> unemployment.ts attach(unemployment.ts)
> unemployment.ts
> unemployment.ts plot(unemployment.ts ...

恩，我看你的code有点混乱，你看看我的这个，应该会好一点。

> unemployment.df<-read.table(file.choose(),header=T)
> attach(unemployment.df)
> unemployment.ts<-ts(unemployment,frequency=12,start=1956)
> plot.ts(unemployment.ts,main="Canadian total unemployment figures(thousands) 1956-1975",xlab="year",ylab="unemploymentfigures(thousands)")

z-score

看完了我马上给你回答。

341 Assignment 1多时候due? 我得好好坐下来看一看，我怕我回答得不全面。

~CHRISTY~

好像還沒進來過這裡呢 341的assn 明天due

水鱼皇后

原帖由 z-score 于 2008-3-18 22:36 发表
看完了我马上给你回答。

341 Assignment 1多时候due? 我得好好坐下来看一看，我怕我回答得不全面。

明天due 我也在等你的回答...

z-score

明天早上回答你好吗？谢谢合作。

z-score

原帖由 chingk 于 2008-3-18 13:53 发表
i hv a question about 341 assn as well

A brewing company has an idea for a new range of “alco-pops”. These are flavoured alcoholic
drinks aimed at the youth (18 years +) market. One of the  ...

天哪，明天交。

在短暂的时间内我可以想到，
Advantages: The electoral roll is the most up to date database to sample people from based on age. Everyone should be legally enrolled to vote at the age of 18. The electoral roll is readily accessible and is at a relatively low cost.

Disadvantages: No everyone on the electoral roll has the internet or uses the Web2.0 websites.

希望下次能早点问我，这样能给我更多一点时间。

z-score

哦, 网络不好, 怎么回帖重复了.

[ 本帖最后由 z-score 于 2008-3-19 09:34 编辑 ]

z-score

原帖由 天外飞猪 于 2008-3-18 18:05 发表
请问。STATS108
第2题的那个survey。
A group of biologists is interested in surveying the abundance of barrel cactus in a particular desert. They divide the desert area up into 1200 equal sized  ...

When you take a sample, you will get sampling error.

e) Hint, blocking, 上面有一个帖子已经解答了。那里解释了blocking的定义和运用方式。

f) 说得对。不过你再看看bakery promotion types, 好像两个都有discount.

h) 这个问题上面的帖子也解答过。It's asking you whether you can make a causation statement. Hint, observational study and experiments.

z-score

我的回答对你们有帮助吗？

[ 本帖最后由 z-score 于 2008-3-18 23:51 编辑 ]

poison_ivy

很有帮助~~
非常感谢~~~