The Student Room Group

Edexcel S2 - 27th June 2016 AM

Scroll to see replies

Original post by RGBlinkFrayXx
Thanks! I honestly can't remember how I managed to get 2/3... Although that may be because the equations were incorrect. If that's the case, even if I still have F(2) is zero and F(3) is one, do I get zero? Or can I get a mark just for saying F(2) is zero and F(3) is one? Any opinions? Sorry for bugging you so much 😅



No need to apologising - its the holiday and I'm perfectly satisfied spending countless hours discussing exams haha !
I'm pretty sure you would get M1 for using the fact that F(2)=0 and F(3)= 1, and also bare in mind that if you got some sort of equation and used it to find K then you may pick up a method mark ! fingers crossed for you mate hahah
Original post by taichingkan
No it wasn't that simple. (b+a)/2 only applies for a uniform continuous. When you have E(A) that is effectively pi*E(R^2) which is not a uniform continuous distribution since you have the R squared.


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?
Original post by Student403
*takes a screenshot for August*


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*
Original post by RGBlinkFrayXx
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?


Unfortunately I think all 4 cause that was a major concept error, not a careless mistake... Sorry :frown:
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!
Original post by taichingkan
Unfortunately I think all 4 cause that was a major concept error, not a careless mistake... Sorry :frown:


No worries. What do you think 66/75 would be in terms of UMS?
Original post by taichingkan
No it wasn't that simple. (b+a)/2 only applies for a uniform continuous. When you have E(A) that is effectively pi*E(R^2) which is not a uniform continuous distribution since you have the R squared.

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
Original post by taichingkan
No it wasn't that simple. (b+a)/2 only applies for a uniform continuous. When you have E(A) that is effectively pi*E(R^2) which is not a uniform continuous distribution since you have the R squared.


hey for this question, I correctly found what E(R) and E(R^2) was and I even wrote the correct answer for E(A) but I underlined my other incorrect E(A) which was 49pi... do you think I'd still get like 3/4 cause I had all the correct working but just my final answer wasn't correct ?
Lol of all the things to slip up on I got the variance in the first question wrong. All right other that that it looks like, beaming.
Was the answers like (151/3)pi
Original post by RGBlinkFrayXx
No worries. What do you think 66/75 would be in terms of UMS?


Well according to 2015 boundaries that would be like 79ums, but considering boundaries will likely drop I would say you're gonna get about 82-85 for that... thats me being optimistic so don't come crying to me on results day hahah !
Original post by DesignPredator
Was the answers like (151/3)pi


yeh
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
Original post by RGBlinkFrayXx
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
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 !
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 ?
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*?
Original post by RGBlinkFrayXx
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)
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 ...
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 :'(

Quick Reply

Latest