数学M/S Paper 2讨论专区

chuen1509

請問SPM ADD MATH  不是很好 just credit  拿STPM 的math s , 會很吃力嗎？？要如何應付MATH S？ 補習嗎？？

hongji

回复 381# chuen1509


    还是要努力多做练习。。

hongji

X is a normal random variable with mean 84 and variance 12 , find
P( l X-84 l  2.9 )

这个X在里面了哦。。。不会

chuen1509

回复 382# hongji


   那需不需要補習？有那裏的補習老師比較好？你可以推薦給我幾本練習本嗎？？

hongji

1)A box contains 5 red bulbs , 4 blue bulbs and 3 yellow bulbs.Three bulbs are selected at random from the box.

a)Find the probability that all the three bulbs are of different colours.
  是不是 5C1*4C1*3C1 / 12C3


b)Find the probability that the three bulbs are of different colours if it is known that one of them is yellow.

hongji

回复  hongji


   那需不需要補習？有那裏的補習老師比較好？你可以推薦給我幾本練習本嗎？？
chuen1509 发表于 20-3-2011 07:29 PM

    我有买longman和federal 的
    做练习的话是做longman的，每一课每一part我有做longman给的练习
(虽然不知道这样能不能更会但是还是做多比较好）
    我没有补习没钱去><
    你可以和你朋友去补习的啊
    如果补习好像老师比较会教更多吧

peaceboy

回复 383# hongji


    多过还是少过？

peaceboy

回复 385# hongji


    1)A box contains 5 red bulbs , 4 blue bulbs and 3 yellow bulbs.Three bulbs are selected at random from the box.

a)Find the probability that all the three bulbs are of different colours.
  是不是 5C1*4C1*3C1 / 12C3
对


b)Find the probability that the three bulbs are of different colours if it is known that one of them is yellow.


P(Y) = 1-  (3C0 * 9C3)/ 12C3

p(D n Y)=5C1*4C1*3C1 / 12C3

P(D l Y)= p(D n Y) / P(Y)

还真的没人要solve

hongji

回复 387# peaceboy


   

X is a normal random variable with mean 84 and variance 12 , find P( l X-84 l  >2.9 )

hongji

回复 388# peaceboy


    如果你去读大学了
    这里数学怎么办啊
    呵呵==


Of the people who enter a large shopping mall,it has been found that 70 percent will make at least one purchase .A sample consisting of 50 individuals is chosen at random from a large shopping mall.What is the probability that at least 40 people make one or more purchase each


有2个做法哪个是对的？

       ^                                           ^
1）P(P>/[39.5/50])             还是    P(P>[40/50])  ?

hongji

The monthly incomes of workers in the Prai industrial estate is believed to be normally distributed with mean (U) and standard deviation. A sample consisting of 64 workers is selected at random from this and their incomes(RMＸ）are summarised as Exi=27200(E :sum of ...) and E(xi-x`)^2=145152
所以their mean is 425 standard deviation is 48
                                      _
还有啊因为没有那个符号(x`=x )

find the minimum montly income,to the nearest RM1,of a worker chosen at random from this area whose income is in the highest 5% among all the workers in this area.
    _      _
if (x-5 , x+5) represents a 95% confidence interval for mean(U) , determne the minimum sample size n required.

hongji

in a survey made on 400 mini-markets chosen at random in a certain country, it is found that 136 of them sell one type of household product A which contains a certain chemical ingredient higher than the level specified by the goverment .
find a 95% confidence interval for the percentage of mini-markets all over country which sells the household product A containing the chemical ingredient higher than the level specified by the goverment.

peaceboy

回复 389# hongji


    P( l X-84 l  >2.9 )
P(l z l > 2.9/(12)^(1/2)) = P(z> 2.9/(12)^(1/2)) + P(z<2.9/(12)^(1/2))

peaceboy

回复 390# hongji


    都对呱
我以前老师说math S可以不做continuity correction的
不过考试我还是照做

有continuity correction是正确的做法

peaceboy

回复 391# hongji


    其实我很懒惰想
等我有feel了再回来作

hongji

回复 394# peaceboy


    continuity correction
    意思是39.5那些吗？

hongji

回复  hongji


     其实我很懒惰想
等我有feel了再回来作
peaceboy 发表于 30-3-2011 07:44 PM

    噢我明白的

數學神童

A factory producing electronic equipments obtain 40% of the electronic components from supplier A, 25% from supplier B and 35% from supplier C. The percentage of defective electronic components supplied by supplier A, B and C are 5% , 2% and 1% respectively.
a)Find the probability that an electronic component selected randomly from overall supply to the factory, is defective.
b)Find the probability , from two electronic components selected randomly from the overall supply as received by the factory:
    i)At least one electronic component is defective
   ii)Both the electronic components are defective and supplied by supplier A.

Please help me to solve this question.....This is the past year question for 1999.

數學神童

A study on 100 visitors to a book fair shows that 60 visitors have seen the advertisement about the fair. Out of 40 visitors who make purchases, 30 have seen the advertisement. Find the probability that a visitor who has not seen the advertisement makes a purchase.

cheesit92

回复 398# 數學神童


   (a) 0.4 x 0.05 + 0.25 x 0.02 + 0.35 x 0.01 = 0.0285
(b) i. D~B(2,0.0285)
P(D>=1) = 1 - P(D=0)
             = 1 - 2C0 (0.0285)^0 x (0.9715)^2 = 0.056188

ii. p= 0.4 x 0.05 = 0.02
AD~(2,0.02)
P(AD=2) = 2C2(0.02)^2 x (0.98)^0 = 0.0004