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Author Topic: S1 and S2 DOUBTS HERE!!!!  (Read 54388 times)

Offline Arthur Bon Zavi

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Re: S1 DOUBTS HERE!!!!
« Reply #180 on: May 17, 2011, 04:02:26 pm »
Peter will continue UNTIL he has got an answer wrong. It will then not matter him getting answer by being helped.

Working in attachment :
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Offline mdwael

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Re: S1 DOUBTS HERE!!!!
« Reply #181 on: May 18, 2011, 06:38:42 pm »
Can someone suggerst me really hard edexel S1 past papers for practice?
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Offline igext

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Re: S1 DOUBTS HERE!!!!
« Reply #182 on: May 19, 2011, 10:33:45 am »
Quote from: Saladin on May 04, 2010, 12:44:39 pm
Hey, I do Edexcel S1, please post all your doubts here!!!

hello
i just have one question
June 2008 Q7(c)
question about normal dist.
I dont get why they are multiplying by 3?
Thank you loads in advance.
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**RoRo**

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Re: S1 DOUBTS HERE!!!!
« Reply #183 on: May 19, 2011, 01:51:59 pm »
Guys, I need help in those theoretical questions that they ask, how do you 'apply' your knowledge of the subject there?
Like is there any rule sort of thing that we need to know, for example in mechanics by assuming that the string is inextensible, the acceleration is the same, so is there anything similar to that in S1?
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**RoRo**

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Re: S1 DOUBTS HERE!!!!
« Reply #184 on: May 19, 2011, 02:28:58 pm »
Guys try solving Solomon paper L and someone tell me why did they take the value of n as 121 to find the Quartiles and not 120 in Q7a.

 http://www.freeexampapers.com/past_papers.php?l=Past_Papers%2FA+Level%2FMaths%2FEdexcel%2FS1%2FSolomon/
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Offline mdwael

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Re: S1 DOUBTS HERE!!!!
« Reply #185 on: May 19, 2011, 06:01:28 pm »
Quote from: igext on May 19, 2011, 10:33:45 am
hello
i just have one question
June 2008 Q7(c)
question about normal dist.
I dont get why they are multiplying by 3?
Thank you loads in advance.

Because you are picking 3 bags at any order. so you can go like this. let the bag which is less than 53 be A and if its more than 53 be B.
They want 2 Bs and 1 A,

If they are chosen at random the arrangement can come

 B B A

 B A B

 A B B

so there are 3 ways of getting 2 bags which weigh more than 53 and one bag which weighs less. so you multiply the probabilities and then add them or just find the probability once and multiply it by 3. Hope this helps.
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Offline Tohru Kyo Sohma

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Re: S1 DOUBTS HERE!!!!
« Reply #186 on: May 19, 2011, 06:11:41 pm »
ok...i have my s1 exam coming(i mean we all do :P)...so i have a few doubts.......its from may/june 2007 qns 1....i dont get it at all
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**RoRo**

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Re: S1 DOUBTS HERE!!!!
« Reply #187 on: May 19, 2011, 06:45:18 pm »
Quote from: mimiswift on May 19, 2011, 06:11:41 pm
ok...i have my s1 exam coming(i mean we all do :P)...so i have a few doubts.......its from may/june 2007 qns 1....i dont get it at all

For part a)
r=Sxy/?(SxxSyy) = -808.917/?(113573 x 8.657) = -0.816 (3sf)
and by the way, the formula is given in the formula booklet.

b) Since the product moment correlation coefficient is a negative value, then this means that as one value increases, the other value decreases, so in this case, the houses become cheaper as they become further away from the station.

c) The product moment correlation coefficient is not affected by coding i.e. if you add, subtract, multiply or divide the original data for coding, it'll not change, so it's value is the same.
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Offline Tohru Kyo Sohma

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Re: S1 DOUBTS HERE!!!!
« Reply #188 on: May 19, 2011, 06:49:09 pm »
wait.....is this page for edexcel paper???....because im doing CIE!!!opsie :-[
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Offline Ghost Of Highbury

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Re: S1 DOUBTS HERE!!!!
« Reply #189 on: May 19, 2011, 06:55:45 pm »
Quote from: mimiswift on May 19, 2011, 06:11:41 pm
ok...i have my s1 exam coming(i mean we all do :P)...so i have a few doubts.......its from may/june 2007 qns 1....i dont get it at all

Let x = t - 35

Therefore, Mean = -15/12 = -1.25
However, this is the mean for (t-35)

The mean for t = -1.25 + 35 = 33.75 ~ 33.8

The s.d for x (i.e t-35) is the same as the s.d for t

So, S.d = sqrt(Sum(x_i^2)/12 - (mean^2(for t-35)

= sqrt((82.23/12)-(-1.25)^2 = 2.3
« Last Edit: May 19, 2011, 06:58:55 pm by Ghost Of Highbury~ »
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Offline Tohru Kyo Sohma

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Re: S1 DOUBTS HERE!!!!
« Reply #190 on: May 19, 2011, 06:59:02 pm »
thanks alot!!!
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**RoRo**

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Re: S1 DOUBTS HERE!!!!
« Reply #191 on: May 19, 2011, 07:00:58 pm »
Guys try solving Solomon paper L and someone tell me why did they take the value of n as 121 to find the Quartiles and not 120 in Q7a.

 http://www.freeexampapers.com/past_papers.php?l=Past_Papers%2FA+Level%2FMaths%2FEdexcel%2FS1%2FSolomon/

& Solomon paper J, why are they taking the value of n as 56 instead of 55 in Q1a?
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**RoRo**

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Re: S1 DOUBTS HERE!!!!
« Reply #192 on: May 19, 2011, 07:01:42 pm »
Quote from: mimiswift on May 19, 2011, 06:49:09 pm
wait.....is this page for edexcel paper???....because im doing CIE!!!opsie :-[

I thought you're Edexcel because the S1 paper is actually tomorrow.
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Offline Tohru Kyo Sohma

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Re: S1 DOUBTS HERE!!!!
« Reply #193 on: May 19, 2011, 07:05:38 pm »
Quote from: The Secret on May 19, 2011, 07:01:42 pm
I thought you're Edexcel because the S1 paper is actually tomorrow.
no im CIE.......its ok.......BEST OF LUCK for ur s1 exam tomorrow!!!ALL of u ;)
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Offline daas

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Re: S1 DOUBTS HERE!!!!
« Reply #194 on: May 19, 2011, 07:56:36 pm »
 hi,

1 doubt...perhaps the last one
may/jun 2010 Q3 part e) ???
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