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Edexcel (IAL): Statistics 2, 29th January 2016

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how did you find it guys?
how did you find it guys?
Reply 22
Right, got distracted by an integral. S2 answers:

1(b) B(20, 0.35)
(c) P(x > 10) = 0.0532

2 (a) a= -4. b= 12
(b) c = 1/2
(c) E(X^2) = 112/3
(d) 1/2

3(a) 0.00138
(b) 0.0174
(c) 0.0262

4(a) d= 2
(b) 29/64
(c) Q_1 =
(d) median = 1.565
(e) k = 0.594

5(a) (1e1)2(1-e^{-1})^2
(b) e2e^{-2}
(c) w = 85
(d) λ=10\lambda = 10
(e) x16x \geq 16

6 (b) E(X) = 5.4
(c) F(x) = 0, 1, blah - important bit x31270+1x2180\displaystyle \frac{x^3 - 1}{270} + \frac{1-x^2}{180}
(d) 0.5769
(e)P(x > E(x)) > 1/2 so positively skewed.

7(a) 0.0612
(b) No change. X >= is the C.R 14 is not in the C.R
Reply 23
Original post by Zacken
Haha, no it's fine. My school does the IB and their policy is that I need to do French as First Language, which at IB-Level is very hard (for me), imagine English Literature and Language at A-Level combined into one and then turned into French. Not to mention that all the coursework for the subjects was nonsense, you have to do a philosophy course, their top maths course was a joke compared to A-Levels and there was no way I was getting into Cambridge with that system. I pestered them for a while about giving me more flexibility, letting me drop French to at least second language level, they were having none of it. I got really fed up and decided that I'd just get on with my own stuff and it's been working out fantastic so far. :yep:


That was a good comparison, actually, given my hate for English Literature and Language (no offence, writer boy :wink: ). Where are you when my IB elitist friends talk about how much better they are? :tongue: I think they removed Further Maths HL, apparently that was a beast. I guess you did the wise thing, and hey, you're already halfway there to where you want to be!
Reply 24
Original post by Zacken
Right, got distracted by an integral. S2 answers:

1(b) B(20, 0.35)
(c) P(x > 10) = 0.0532

2 (a) a= -4. b= 12
(b) c = 1/2
(c) E(X^2) = 112/3
(d) 1/2

3(a) 0.00138
(b) 0.0174
(c) 0.0262

4(a) d= 2
(b) 29/64
(c) Q_1 =
(d) median = 1.565
(e) k = 0.594

5(a) (1e1)2(1-e^{-1})^2
(b) e2e^{-2}
(c) w = 85
(d) λ=10\lambda = 10
(e) x16x \geq 16

6 (b) E(X) = 5.4
(c) F(x) = 0, 1, blah - important bit x31270+1x2180\displaystyle \frac{x^3 - 1}{270} + \frac{1-x^2}{180}
(d) 0.5769
(e)P(x > E(x)) > 1/2 so positively skewed.

7(a) 0.0612
(b) No change. X >= is the C.R 14 is not in the C.R


Seems like you had a good S2 exam. Couple of friends told me it was difficult.
Reply 25
Original post by aymanzayedmannan
Seems like you had a good S2 exam. Couple of friends told me it was difficult.


Not sure. Nobody's checked my answers, they could all be wrong. :tongue: - there were some weird explanation questions.

"Explain why the Poisson approximation is better than the Normal approximation in [specific] case". Not sure if it was hard though, there weren't any sampling distributions questions, which makes me sad. I like those and they usually bring down the boundaries. There were two nice PDF/CDF questions, that made the paper easier than normal, imo, but S2 IAL boundaries have stayed surprisingly constant over the years.
Reply 26
Original post by Zacken
Not sure. Nobody's checked my answers, they could all be wrong. :tongue: - there were some weird explanation questions.

"Explain why the Poisson approximation is better than the Normal approximation in [specific] case". Not sure if it was hard though, there weren't any sampling distributions questions, which makes me sad. I like those and they usually bring down the boundaries. There were two nice PDF/CDF questions, that made the paper easier than normal, imo, but S2 IAL boundaries have stayed surprisingly constant over the years.


It's always been around 67-69 for an A* - kinda brutal 'cause if you mess up one part you miss the A*, but then again S2 is supposed to be easy!

I think you're the only one who sat this exam... :tongue:
Reply 27
Original post by Leniaeco
how did you find it guys?


You there fam
Reply 28
Original post by aymanzayedmannan
It's always been around 67-69 for an A* - kinda brutal 'cause if you mess up one part you miss the A*, but then again S2 is supposed to be easy!


Isn't that what the other modules are like as well? I'm not very good with boundaries. Don't pay much attention to them. :colondollar:

I think you're the only one who sat this exam... :tongue:


Is S2 meant to be this unpopular? :lol:
Original post by Zacken
Right, got distracted by an integral. S2 answers:

1(b) B(20, 0.35)
(c) P(x > 10) = 0.0532

2 (a) a= -4. b= 12
(b) c = 1/2
(c) E(X^2) = 112/3
(d) 1/2

3(a) 0.00138
(b) 0.0174
(c) 0.0262

4(a) d= 2
(b) 29/64
(c) Q_1 =
(d) median = 1.565
(e) k = 0.594

5(a) (1e1)2(1-e^{-1})^2
(b) e2e^{-2}
(c) w = 85
(d) λ=10\lambda = 10
(e) x16x \geq 16

6 (b) E(X) = 5.4
(c) F(x) = 0, 1, blah - important bit x31270+1x2180\displaystyle \frac{x^3 - 1}{270} + \frac{1-x^2}{180}
(d) 0.5769
(e)P(x > E(x)) > 1/2 so positively skewed.

7(a) 0.0612
(b) No change. X >= is the C.R 14 is not in the C.R


Did you know that this exam can be taken anywhere in the world? So some people could have read your answers before going in to sit the exam. I hadn't realised previously how early you were putting your answers up.
Reply 30
Original post by tiny hobbit
Did you know that this exam can be taken anywhere in the world? So some people could have read your answers before going in to sit the exam. I hadn't realised previously how early you were putting your answers up.


Nopes. IAL exams are coordinated so that you can talk about it as soon as you leave the exam hall. I'd doubled checked with the community team. I had the same concerns initially after my first physics exam and was warning people not to post answers, but was then reassured by two different mod members who checked with whatever that it was fine :yep:
Original post by Zacken
Nopes. IAL exams are coordinated so that you can talk about it as soon as you leave the exam hall. I'd doubled checked with the community team. I had the same concerns initially after my first physics exam and was warning people not to post answers, but was then reassured by two different mod members who checked with whatever that it was fine :yep:


Your answers for S2 were posted this morning at 8.27 UK time.

When I asked Graham Cumming at Edexcel about this this morning, his reply was
"IAL exams can be taken anywhere outside the UK - so if it's being taken anywhere west of the Greenwich meridian there's a chance that candidates will have seen the posting."

Your M2 answers were even earlier, 7.50 UK time.
(edited 8 years ago)
Reply 32
Original post by tiny hobbit
...


That's disturbing. :s-smilie: Thanks for letting me know. I'll double check with the CT/IAL Edexcel department directly. Because, as far as I know, IAL was made to avoid this precise timing issue.
In the question of 6, I found the skewness was negative as mean is smaller than median. This is because that P(x>E(x)) is greater than 0.5 so the value of e(x) has to be smaller than the value of median. (Not sure though.) P(x<E(x) was also 0.4xxxx.. In this question, was the mode 7 ? as f(x) = x^2/90 - x/90 ; 5.4 of mean is smaller than 7 of mode, showing mean is smaller than mode as well. Therefore, Mean < median < mode is proved. Am i wrong..?

In the question of 7(B), which one was i supposed to use between two and one tailed ? My approach was two - tailed one, finding 0.0342 is bigger than 0.025, which shows there is less evidence to claim that the rate of fish caught has been changed after buying the equipment. The reason why i used two-tailed was there was no explicit mention about increase. The question just said that there was any change after buying equipment.

Could anyone tell me whether i am right or not ? Please!!
Hi as soon as you finish post answers so we can check. I am very anxious.if i do not go well in s2 i am not going to study in uk

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