数学M/S Paper 2讨论专区

Log

那两个人，A and B
排法有:  AB ,BA
是不是？ so times 2

harry_lim

原帖由 Log 于 10-11-2009 11:33 PM 发表
那两个人，A and B
排法有:  AB ,BA
是不是？ so times 2

哦～
明白了

harry_lim

我又有題目不會了～
In a country, 78% of comsumers are in favour of government control over prices. A random sample of 400 consumers is selected.

(a) Find the mean and standard deviation of the distribution of the sample proportion.
(b) Find the probanbility that the sample proportion is at least 5% lower than the population proportion.

(a)的我已經算出來了～mean = 0.78,standard deviation = 0.02071
(b)的我不會做～教我這一題==

Log

请问mean and s deviat. 你是这么做到的呢?
are u sure mean and SD are correct?

harry_lim

肯定对的啊~不然你参考sampling & estimation的chapter好了~

Log

sampling and estimation??
其实我是拿maths t的

harry_lim

原帖由 Log 于 12-11-2009 11:20 PM 发表
sampling and estimation??
其实我是拿maths t的

原來你是math T的
paper 2你只學到probability,probability distribution,data description我們都有學的東西罷了

harry_lim

我希望今年是出graphiced method

harry_lim

有哪一個大大可以教我一下simplex method怎樣算～
tableau 1我會～
但是到了tableau 2 or 3的我就不會算了

walrein_lim88

我可以教你﹐可是這裡如何教??

harry_lim

原帖由 walrein_lim88 于 26-11-2009 08:37 PM 发表
我可以教你﹐可是這裡如何教??

你寫在一張紙～
可以？

walrein_lim88

然後??我沒有SCANNER。。不過通常我教我朋友MATHS都是用MSN的。。哈哈

harry_lim

好啊～用msn好了～
你add我～
love_in_a_planet@yahoo.com.tw

walrein_lim88

sorry ah..must type in english..coz maths learn in english..please allow me to type in english..thx.. n sorry

to do simplex
1st step: identify which coeficient of x, y ( or z if got) is the smallest at the row z
2nd step: each solution divided by its coeficient of x, y, or z ( the smallest coeficient u have chosen in 1st step)
3rd step: identify the smallest solution after u divide , den tat one is ur pivot row.
4th step: each number in pivot row divided by its coeficient of x, y or z( the smallest coeficient u haven chosen in 1st step)
5th step: change the old row to new row by using this formula:
old row - (coeficient of ITS x,y or z( smallest column u haven chosen)  TIMES pivot row)

this 5 steps are repeated again for each tableau until u all the number in row z is positive.

harry_lim

矛盾下
希望它再出simplex method
出graphic method也好


還有～probability我是完蛋了的

walrein_lim88

好矛盾。。不过现在觉得SIMPLEX容易吧

harry_lim

原帖由 walrein_lim88 于 30-11-2009 07:28 PM 发表
好矛盾。。不过现在觉得SIMPLEX容易吧

只是比較浪費時間一點點
graph的我怕畫錯


time series也是很夠力下

harry_lim

confidence interval的final answer要怎樣寫？
本來是算到。。。for example, (7.002 , 7.008) <proportion

是寫7.002 < p < 7.008
醬的？

walrein_lim88

答案是（ XXXX  XXXX）
confidence interval的final answer要怎樣寫？
本來是算到。。。for example, (7.002 , 7.008) <proportion

是寫7.002 < p < 7.008
醬的？

shud be (7.002, 7.008)

harry_lim

原帖由 walrein_lim88 于 30-11-2009 11:01 PM 发表
答案是（ XXXX  XXXX）
confidence interval的final answer要怎樣寫？
本來是算到。。。for example, (7.002 , 7.008)  

掛號寫那兩個數字就對了咯？