2008 First Semester STATS课程官方问答贴

Vy2

原帖由 阴雨天 于 2008-5-27 20:01 发表
求救  101 ASMT Q2(b)我得出的P-value好大啊! 0.756.....
这属于正常情况吗? 还是说我肯定算错了? 我看了一下,得出这么大的P-value 的主要原因是我的T-test的得数是个小于1的数. 是不是说我算错了??  还请做过 ...

its same as mine.. and i matched it with my frds.. it indicates no evidence

z-score

原帖由 天外飞猪 于 2008-5-27 19:40 发表
atm。。
108第三题为什么只有case3是nothing learned？那case5为什么不是nothing learned?

因为case 5 is statistically significant as the P-value is 0.

z-score

原帖由 Vy2 于 2008-5-27 17:48 发表
OMG.. what is the validity of the F-test assumptios..???
i found the assumptions for F-test in coursebook..
but validity..??? what am i suppose to do... >

If all the assumptions are satisfied, then the F-test is valid.

So this question is asking you to see whether the F-test assumptions are satisfied.

z-score

原帖由 ~Kurosagi~ 于 2008-5-27 17:02 发表
question 1 a 的step 7 我們要怎么做?

按照course book的jam example來做嗎??

還是??

Step 7是P-value吗？不好意思，没有coursebook, jam example记得。恩，按照single mean的example作就好了。

z-score

原帖由 阴雨天 于 2008-5-27 18:12 发表

原来如此! 谢谢!
还有个问题.step 7 判断observed difference有多statistically的依据是什么??? P-value? 划分的界限分别是什么?

Assignment题目：
In addition, travel agents consider
an average difference between the types of display of less than 14 seconds would be of no
consequence, whereas an average difference of 14 seconds or more could result in
considerable cost savings.

意思就是-14和14以外的都是practically significant, 记住，要是整个的ci在外面才是，不然是unknown.

z-score

原帖由 璐秋孟孟 于 2008-5-27 19:58 发表
请问4(a)和5(a)怎么Comment on any features in the plot(s)呢？书里都是dots plot.

Boxplots的comment:

1. Median
2. Range, inter quartile range
3. Skewness
4. Outliers

z-score

原帖由 阴雨天 于 2008-5-27 20:01 发表
求救  101 ASMT Q2(b)我得出的P-value好大啊! 0.756.....
这属于正常情况吗? 还是说我肯定算错了? 我看了一下,得出这么大的P-value 的主要原因是我的T-test的得数是个小于1的数. 是不是说我算错了??  还请做过 ...

原帖由 Vy2 于 2008-5-27 20:08 发表



its same as mine.. and i matched it with my frds.. it indicates no evidence

刚做了一下，就是那个数。

Vy2

for 7d the validity one..

i looked at the worked example no.14.. it said: "The
assumption of equal population standard deviations is reasonable as the ratio of highest to lowest
sample standard deviations (1.399) is less than 2."

my answer is about 5.6332 (4 d.p.)
so does tat mean it is NOT reasonable?

天外飞猪

atm
108第三题d是case3和5都是nothing to learned  么？还是只有3？
还有1b要怎么写呢？
什么情况下包括true mean?

liner

请问 108 Q4 & Q5 都是paried sample嘛？

天外飞猪

atm.
108第三题d.case 3&5都是nothing to learned?还是只有3？
还有1b要怎么写呢？

天外飞猪

atm.
108第三题d.case 3&5都是nothing to learned?还是只有3？
还有1b要怎么写呢？、什么情况下才是包括了true mean?
这里的　true　mean又是什么？？？

punklink

Question 6 c)

Scenario 1 and 2 ??

拂洛依德

１０８　我不会做第７题！读不懂！紧急求救！明天就交了～拜托拉！

luvwei

Scenario 1:         Full 2 (quantitative)                State (qualitative)
Scenario 2:         Part 1 (quantitative)                State (qualitative)


如果我这个写的是对的那 s1,s2,s3 ,s5 都要用side by side plot lar????

luvwei

full 2 and part 1 . can it be qualitave as well?
coz its divided in boundaries?

z-score

原帖由 Vy2 于 2008-5-27 20:33 发表
for 7d the validity one..

i looked at the worked example no.14.. it said: "The
assumption of equal population standard deviations is reasonable as the ratio of highest to lowest
sample stand ...

Yes you are right, the equal standard deviation assumption is not satisfied.

z-score

原帖由 天外飞猪 于 2008-5-27 20:35 发表
atm
108第三题d是case3和5都是nothing to learned  么？还是只有3？
还有1b要怎么写呢？
什么情况下包括true mean?

只有case 3是learnt nothing useful.

true  mean那道题前面已经回答了，是we do not know.

z-score

原帖由 liner 于 2008-5-27 20:35 发表
请问 108 Q4 & Q5 都是paried sample嘛？

Question 4 is paired, question 5 is two sample.

z-score

原帖由 punklink 于 2008-5-27 20:50 发表
Question 6 c)

Scenario 1 and 2 ??

原帖由 z-score 于 2008-5-24 21:58 发表

for questions 6 c I got:

B
E
D
C
F

Did anyone else get this too?

前面的回复。

z-score

原帖由 luvwei 于 2008-5-27 21:19 发表
full 2 and part 1 . can it be qualitave as well?
coz its divided in boundaries?

You are right, they are both qualitative. So, not that many side by side plots.

z-score

原帖由 拂洛依德 于 2008-5-27 20:58 发表
１０８　我不会做第７题！读不懂！紧急求救！明天就交了～拜托拉！

全不会？

前面的一些回复都在22和23页，基本没道题都说了。

z-score

大家assignment进度怎么样？还都在做吗？我一会儿想睡了阿。

~Kurosagi~

是
B
E
嗎??

不是E
B
嗎??

拂洛依德

不好意思　我在说Ｑ７（ｃ）　ａｎｄ　（ｆ）！

punklink

umum..

my one is
B
E

punklink

Is

B
E  

or

E
B ?

punklink

原帖由 z-score 于 2008-5-27 21:31 发表


Question 4 is paired, question 5 is two sample.

which of the two tests from B) is more appropriate for these data?

paired, but how to justufy?

Question 5 dont know how to justufy them... ??

punklink

原帖由 z-score 于 2008-5-27 21:38 发表
大家assignment进度怎么样？还都在做吗？我一会儿想睡了阿。

nt finish yet.. last assignment la.. wuwuwuw.. dnt go sleep too early tonight..

punklink

原帖由 拂洛依德 于 2008-5-27 21:46 发表
不好意思　我在说Ｑ７（ｃ）　ａｎｄ　（ｆ）！

have you done 7e) ??