Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

Edexcel S2 - 27th June 2016 AM watch

  • 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%

    Offline

    2
    ReputationRep:
    Anyone know if there a past paper with a similar question to Q5. ?
    Offline

    2
    ReputationRep:
    (Original post by RGBlinkFrayXx)
    Guys, wasn't the E(X) question 53 pi? Because it's the E(X) of a normal distribution so b-a)/2? Where b=81 pi and a=25 pi?
    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.
    Offline

    19
    ReputationRep:
    (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
    Offline

    1
    ReputationRep:
    (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?
    Offline

    19
    ReputationRep:
    (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*
    Offline

    2
    ReputationRep:
    (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
    Offline

    1
    ReputationRep:
    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!
    Offline

    1
    ReputationRep:
    (Original post by taichingkan)
    Unfortunately I think all 4 cause that was a major concept error, not a careless mistake... Sorry
    No worries. What do you think 66/75 would be in terms of UMS?
    Offline

    2
    ReputationRep:
    (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
    Offline

    19
    ReputationRep:
    (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 ?
    Offline

    2
    ReputationRep:
    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.
    Offline

    9
    ReputationRep:
    Was the answers like (151/3)pi
    Offline

    19
    ReputationRep:
    (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 !
    Offline

    19
    ReputationRep:
    (Original post by DesignPredator)
    Was the answers like (151/3)pi
    yeh
    Offline

    2
    ReputationRep:
    (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
    Offline

    2
    ReputationRep:
    (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
    Offline

    19
    ReputationRep:
    (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 !
    Offline

    19
    ReputationRep:
    (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 ?
    Offline

    2
    ReputationRep:
    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*?
    Offline

    2
    ReputationRep:
    (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)
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: August 20, 2016
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.