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Edexcel S2 - 27th June 2016 AM Watch

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    (Original post by kieran1119)
    You get 555-2p=7sqrtp and if you square all of that then you got 4p^2 -2269p + 555^2 =0 and then if you solve it using the quadratic function you get two answers 225 and something else with a point 25 in and as you were finding n it had to be a whole number so 225 was the answer
    Ah thank you, sorry, but how was the 2n derived? As I thought 1.75 (z value) = (55.5 - n) / (0.16n)^0.5
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    For question 7d I got 41.875 but then for some stupid reason rounded it to 41.82 so will I lose the mark because I rounded wrong? Will this affect me getting the marks in the second part? Thanks
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    55.5-0.2n / (0.16n)^0.5 = 1.75
    55.5-0.2n = 0.4*1.75n^0.5
    3080.25-0.04n^2 = 0.49n
    308025 - 4n^2 = 49n
    4n^2+49n - 308025 = 0
    .....
    ....
    .... n = 82. something or 66. something
    how did people get 225?
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    what was that hypothesis testing question i think it was the last part of question 2 or 3
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    I just put n =225 because in all questions I done before that were similar, they always squared the positive root
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    (Original post by NamelessPersona)
    If you square both sides you treat it as a bracket
    how many marks will i lose?
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    (Original post by KFC_Fleshlight)
    55.5-0.2n / (0.16n)^0.5 = 1.75
    55.5-0.2n = 0.4*1.75n^0.5
    3080.25-0.04n^2 = 0.49n
    308025 - 4n^2 = 49n
    4n^2+49n - 308025 = 0
    .....
    ....
    .... n = 82. something or 66. something
    how did people get 225?
    would be root 0.16n not squared
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    can anyone remember the question for Q2 ??
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    (Original post by gameofthrones1)
    how many marks will i lose?
    I would say you would get at least 4, an M1 for using normal approx, an A1 for half cc, and an M1 and A1 for getting to 55.5-0.2n = 1.75*sqrt(0.16n)
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    How were you meant to do the last two questions on the paper?
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    (Original post by bulkybros100)
    How were you meant to do the last two questions on the paper?
    Use E(x) for a discrete distribution as sum of xf(x) and you get around 41.875 I think

    Edit: E(x) = 50(27/40) + 25(13/40) = 41.875

    you would then go on to say that if he sold n bags he would expect 41.875n pounds, but if he removed staples he would get 0.8n*50=40n.
    As 41.875>40, he should not remove staples.
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    (Original post by iMacJack)
    F(3)=1
    F(2)=0

    Then simultaneous



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    (Original post by Yua)
    I done it by integrating and making it equal 1, so working out the area under the graph

    then F(3) =1

    then simultaneous
    ****, im an idiot
    Thanks anyway lads
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    (Original post by NamelessPersona)
    Use E(x) for a discrete distribution as sum of xf(x) and you get around 41.875 I think
    Do you think I would lose a mark for getting 41.875 then accidentally rounding this to 41.82? Thanks
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    (Original post by bulkybros100)
    How were you meant to do the last two questions on the paper?
    (1-0.325)50 + 0.325(25) = E(X) = 41.88

    if he removes staples then because 20% less bins you do 0.8(50) = 40

    40<41.88

    so he should not remove staples as he'd make less money
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    (Original post by TheSammy2010)
    My answers, idk if they are right

    Q1,
    Mean= 1.41
    Variance= 1.4419
    Probabilities; 0.7769, 0.1378, 0.1516

    Q2,
    N=60
    0.0133
    0.0159
    Do not reject Ho (using binomial tables)

    Q3,
    0.75
    151π/3

    Q4,
    K=1/9

    Q5,
    N=225

    Q6,
    P(M=5)= 0.3
    P(M=6)= 0.29
    P(M=7)= 0.12

    N=11

    Q7,

    Mean= 1.2
    Var= 1.92
    P(X>3)= 0.3250
    £41.88 per bin

    He shouldn't as the mean profit of bins would be £40
    Question 2 the hypothesis test was 0.2236 which is more than 0.01 therefore accept null hypothesis

    Question 3 it was 0.5 not 0.75

    Question 4 n was 57

    Rest are right



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    (Original post by economicss)
    Do you think I would lose a mark for getting 41.875 then accidentally rounding this to 41.82? Thanks
    I wouldn't think so but I'm not entirely sure

    Edit: oops misread what you rounded to, yeah I think you would lose a mark
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    What we thinking on grade boundaries then?
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    (Original post by Rey Mysterio)
    What we thinking on grade boundaries then?
    65= A
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    (Original post by Rey Mysterio)
    What we thinking on grade boundaries then?
    Pretty high, probably similar to last year
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    (Original post by TheBigBo)
    It was n and sqrt(n) so the roots of the quadratic are equal to the sqrt of n and then you square the positive one as sqrt(x)≥0
    Omg I spent so long on that question thinking that n couldn't possibly be 15!!! Forgot that it was root(n) 😂
 
 
 
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