2008 First Semester STATS课程官方问答贴

doufu

got it! thanks a lot.
for me ,the hard part is P((AUB)nC)=P((AnC)u(BnC)) (i dont know this without ur tip)
this is only stage 1 course ,but Mark made the assmt so hard ,totally cannot understand him.

阴雨天

101的asgm 5e 题目具体要求我们做什么? 请LZ告诉下~ 谢谢! 有点没看懂.... 5e跟你上传的PDF文件里的5e是一样的.

[ 本帖最后由 阴雨天 于 2008-3-25 15:49 编辑 ]

A00118

assignment 1 q5应该怎么做?

kirstens

yea, it's a little tricky. for these kind of questions, if you get confused, a venn-diagram (I must spell that wrong ,but never mind, you know what i mean) is very helpful.
125 is an interesting course. don't worry too much, you gotta enjoy it!

Thank t-multiplier scored for me. Actually I sometimes found I almost forget about what I've learnt. It's quite helpful to come back here and get myself to think.

[ 本帖最后由 kirstens 于 2008-3-25 16:55 编辑 ]

z-score

原帖由 阴雨天 于 2008-3-25 15:48 发表
101的asgm 5e 题目具体要求我们做什么? 请LZ告诉下~ 谢谢! 有点没看懂.... 5e跟你上传的PDF文件里的5e是一样的.

恩，第五题其实每年都是一样的。你们可以参考我上载的past assignment answers. Question 5e 就是让你画出来那个表格。

[ 本帖最后由 z-score 于 2008-3-25 17:03 编辑 ]

A00118

i am asking stats125 Q5..not stats101....:(

z-score

原帖由 kirstens 于 2008-3-25 16:50 发表
yea, it's a little tricky. for these kind of questions, if you get confused, a venn-diagram (I must spell that wrong ,but never mind, you know what i mean) is very helpful.
125 is an interes ...

Thank you kirstens for your help, I opened this post for the same reason. I hope we can both keep our stats sharp.

z-score

原帖由 A00118 于 2008-3-25 16:59 发表
i am asking stats125 Q5..not stats101....:(

Sorry, 现在马上给你看。

看了直后：

我对这道题不缺定，但是我想if you integrate a probability function over the entire domain, you should get 1.

希望哪位probability高手指点我们一下。

[ 本帖最后由 z-score 于 2008-3-25 17:11 编辑 ]

水鱼皇后

原帖由 303B25 于 2008-3-25 12:25 发表
for 4 i got

(a) 4/5, 1/5, 1/5, 4/5
(b) 1/1250
(c) 13/50, 89/250
(d)
(e)
(f) 0.4888

i got same answers...

A00118

solved...............

[ 本帖最后由 A00118 于 2008-3-25 19:40 编辑 ]

没蚊香的黑夜

STATS 108 THANKS
1. Which one of the following statements is false?

If blocking is used in the design of an experiment, then there is nothing to be gained from using randomisation in that design.

In experiments blocking is used to ensure fair comparisons between the treatments with respect to the other factors the experimenter knows are important.

Only a well designed and well executed experiment can reliably establish causation.

An observational study is often used for identifying possible causes of effects.

Experiments should use some form of random assignment of experimental subjects to treatment groups in an attempt to make the treatment groups as similar as possible in every way except for the treatment being used.

2. In a web survey of approximately 2000 Stage 1 Statistics students, 915 responded.
The students were asked for their birth date and how long they had lived in New Zealand. From this information, values can be found for the variable Percentage of life lived in New Zealand.
Which one of the following statements is not a potential problem when analysing the responses from the survey?

Students may interpret the question "How many years have you lived in New Zealand?" differently, thus question effects may exist.

Percentage of life lived in New Zealand was not one of the questions the students answered.

There will be nonsampling errors, and it will be virtually impossible to determine how badly they will affect the results.

Since this was a web survey, there may be survey-format effects.

The students who answered the web survey were self-selected.

3. TABLE        VISITOR ARRIVAL     AVERAGE SPEND

AUSTRALIA          122545                          XXXXX
UK                          XXXX                          XXXXX
USA                              XXX                          XXXXX
ASIA                       XXXX                          XXXXX

Which one of the following modifications to Table 1 would not improve the table for presentation purposes?

Round the 'Average Spend $NZ' column to the nearest hundred.

Order the rows according to the 'Visitor Arrivals' column.

Add a row of column averages.

Round the 'Visitor Arrivals' column to the nearest ten thousand.

Add a column of row averages.

z-score

原帖由 没蚊香的黑夜 于 2008-3-26 00:54 发表
STATS 108 THANKS
1. Which one of the following statements is false?

If blocking is used in the design of an experiment, then there is nothing to be gained from using randomisation in that d ...

1. Which one of the following statements is false?
If blocking is used in the design of an experiment, then there is nothing to be gained from using randomisation in that design.
Blocking and randomisation concern different aspects of experimental design. Having either blocking or randomisation doesn't mean you can't have the other.

2. In a web survey of approximately 2000 Stage 1 Statistics students, 915 responded.
The students were asked for their birth date and how long they hadlived in New Zealand. From this information, values can be found forthe variable Percentage of life lived in New Zealand.
Which one of the following statements is not a potential problem when analysing the responses from the survey?
Percentage of life lived in New Zealand was not one of the questions the students answered. This is not a potential problem because the question said "values can be found forthe variable Percentage of life lived in New Zealand."

3. Which one of the following modifications to Table 1 would not improve the table for presentation purposes?
Add a column of row averages. Finding the average of visitor arrival and average spending doesn't make sense. Visitor arrival is measured in person and amount spent is measured in $.

[ 本帖最后由 z-score 于 2008-3-26 07:59 编辑 ]

z-score

原帖由 303B25 于 2008-3-26 11:15 发表
ATM

I'm trying to type out the assignment right now but I don't know how to type the complement, can you show me how to type a line on top of stuff please.

Hi 303B25, yep sure thing. Now if you are typing your assignment up in word, you would first need to click insert in the menu bar then click object, scroll down till you find Microsoft Equation 3.0.

z-score

原帖由 303B25 于 2008-3-26 10:36 发表
5(a)

(i) make sure the probability is never negative
(ii) make sure the sum of it =1
(iii)probability of it equal to the integration of the function

not exactly sure with this one, try in ...

Wow, you are so good, I'm so glad I'm not on my own in this post.

z-score

原帖由 303B25 于 2008-3-26 13:38 发表
I use openoffice, that's alright, I'll just write it on, easier.

I use open office on my laptop as well. I tried installing Office 2007 but don't know why it doesn't work on my vista

dk7

Insert -> object -> Formula

SnowDrop

I don't like vista. It's a shame that they installed vista in iMac in the stat lab. What a waste!!!

t-multiplier

Yeah, why did they buy Imacs anyway? To save space?

Thank you 303B25, I'm reading the link you gave me now.

dk7

You see me here... what else could it be? : )

It's just there're too much to think about for what I'm doing at themoment and knowing the stats stuff doesn't mean I don't need mybrain.  Other*** I would have helped z-score on this one...

[ 本帖最后由 dk7 于 2008-3-26 18:23 编辑 ]

t-multiplier

原帖由 dk7 于 2008-3-26 18:15 发表
You see me here... what else could it be? : )

It's just there're too much to think about for what I'm doing at themoment and knowing the stats stuff doesn't mean I don't need mybrain.  Other** ...

Yeah, with the hard questions posted here, I really need all the help and support I could get. Help from dk7, 萨米, SnowDrop and 303B25 are greatly appreciated.

Thank you guys.

dk7

PM me would be good if you need help.  I could see myself being more active in the next half of the year...

当时的理想

HI。。。 STAT 108 的第一个ASSIG。。。 的最后面2个小题。。写小评价那图的。。。请LZ给点小意见。。。。

WORD LENGTH 和WORD NUMBER。。 有些NUMBER 小。。但LENGTH挺大的。。 不知道怎么评价。。

还有那个PLOT.。。

谢谢谢谢。。十分感谢。。。

z-score

原帖由 当时的理想 于 2008-3-26 19:15 发表
HI。。。 STAT 108 的第一个ASSIG。。。 的最后面2个小题。。写小评价那图的。。。请LZ给点小意见。。。。

WORD LENGTH 和WORD NUMBER。。 有些NUMBER 小。。但LENGTH挺大的。。 不知道怎么评价。。

还有 ...

你好，我可以帮你comment, 你能把你的图片贴上来吗？因为每个人的数据都不一样，comment出来的结论也不一样。这个plot的comment主要是看word length和number of words的relationship. For example, is there an increasing relationship or decreasing or no relationship? How is the scatter?