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# Edexcel S2 - 27th June 2016 AM

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• View Poll Results: How did you find the Edexcel S2 exam?
Very hard
145
14.71%
Hard
331
33.57%
Normal
293
29.72%
Easy
152
15.42%
Very easy
65
6.59%

1. (Original post by anndz3007)
What was the answer you got for that, i got 3pi/4 cus i integrate pi R square r, which is (pi r )/16
Is that wromg
I did E(A)=pi*E(R^2), which can be found using Var(X)+(E(X))^2 which gave (151/3)pi
Really small question you guys- for the beginning of the paper, for justifying they cherry thing as being Poisson, could you discuss the idea that the cherries could be found in certain frequencies at a constant rate? Or they were found independently/randomly? Thanks!
Think they're looking for the fact mean is similar to variance
3. (Original post by Armpits)
Tomorrow will probably be the hardest S2 with lots of conditional probabilities and in-context uniform distribution.
wow you were so spot on with the ' in - context ' uniform distribution with the circle question !
4. (Original post by zombaldia)
Think they're looking for the fact mean is similar to variance
I said that the mean was the same as the variance... but my mean and variance were not the same in part a... will i get any marks ?
5. I got variance as 1.58 I think. Don't know how I screwed that up. I got the same mean. For the next part I said they were nearly the same so poisson would be suitable. Would I get the mark? Also grade boundaries for A*?
No worries. What do you think 66/75 would be in terms of UMS?
I'm sorry, I'm not the best person to ask, but I would think that should still get you in the A region (80-90 UMS)
7. (Original post by target21859)
I got variance as 1.58 I think. Don't know how I screwed that up. I got the same mean. For the next part I said they were nearly the same so poisson would be suitable. Would I get the mark? Also grade boundaries for A*?
A* probably looking at anywhere between 67 and 71 ...
8. (Original post by taichingkan)
I did E(A)=pi*E(R^2), which can be found using Var(X)+(E(X))^2 which gave (151/3)pi
Just realised it, the letter R and r confused me that's why ahhh
Did you managed the find n question
I got 1.75= (55.5-0.2n)/root16n, and got minus b^2-4ac so i stop at the multipling step :'(
Yeah, just came on TSR and realised my mistake 😅 Do you think any working out marks are possible here or did I lose all 4?
You might get a mark for saying E(r) =7
10. Whats 55/75?

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11. (Original post by fefssdf)
I said that the mean was the same as the variance... but my mean and variance were not the same in part a... will i get any marks ?
Probably as they were the same to 1 sf or 2sf, techincally. Right sort of concept so probably but i'm not amazing at stats and by no means an examiner
12. (Original post by taichingkan)
I'm sorry, I'm not the best person to ask, but I would think that should still get you in the A region (80-90 UMS)
Thank you for your help! 😊👍🏼
13. (Original post by anndz3007)
Just realised it, the letter R and r confused me that's why ahhh
Did you managed the find n question
I got 1.75= (55.5-0.2n)/root16n, and got minus b^2-4ac so i stop at the multipling step :'(
i think it was root(0.16n) not root(16n), I managed to guess 225 and some other answer in the 300s, rejected cause decimal. So my answer was n=225.
Thank you for your help! 😊👍🏼
It's alright, sorry I couldn't give you a tighter range...
15. (Original post by zombaldia)
Probably as they were the same to 1 sf or 2sf, techincally. Right sort of concept so probably but i'm not amazing at stats and by no means an examiner
ah I hope they just give me the mark lol... cause in the formula book it has both the mean and variance for the poisson distribution as being both lamba so thats why i wrote it down ...
16. c1: 90
c2: 86
s1: 70

c3: 74
c4:78
s2: 55 marks ( maybe a B?)

lol there goes my A
17. (Original post by fefssdf)
ah I hope they just give me the mark lol... cause in the formula book it has both the mean and variance for the poisson distribution as being both lamba so thats why i wrote it down ...
Yeah it'll probably be right. Don't worry about it mate. Only 1 mark too
18. (Original post by fefssdf)
I do think it has got to go down I mean even the final question with Peter and his bins would've confused some people as people assume its more difficult than it actually is, given its at the end of the paper *prays*
Yeah not many people I asked got it

What is your profile pic? XD
19. (Original post by Student403)
Yeah not many people I asked got it

What is your profile pic? XD
Twitter was sending lots of hate towards Peter so hopefully that counts in our favour .

My profile pic is a page of chapter 2 from c3
20. Anyone up for doing an unofficial mark scheme?

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