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    (Original post by Zacken)
    Yeah, nothing difficult, just the combination of boredom and doing it at 3 a.m that made dropped me ~4 marks from silly mistakes whereas the 6 questions in UK 15 were fun and enjoyable (towards the end, at least).
    bruh i scored 70/75 within 30 mins on the ial and 59/75 on the normal.

    I Made mistakes on qn 5 and then made silly mistakes like degree of freedom errors and that was it.
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    (Original post by tazza ma razza)
    bruh i scored 70/75 within 30 mins on the ial and 59/75 on the normal.

    I Made mistakes on qn 5 and then made silly mistakes like degree of freedom errors and that was it.
    It was much the other way around for me: 74/75 in 45 mins in the normal and 70/75 in 40 mins in the IAL, smh.
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    Hardest S3 papers? Have done June 2015, June 2015 IAL and June 2013R which were supposed to be hard, only tough question was 5d on June 2015, although that seems to be universally disliked by everyone on this thread
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    quick qn about the pmcc and srcc

    do we find sxy and sxx of the ranks or the actual data? I assume ranks cos there would be no point of making it (a+b)/2 would it... so would i be right in saying we would do sxy etc with ranks???
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    (Original post by JoshC98)
    Hardest S3 papers? Have done June 2015, June 2015 IAL and June 2013R which were supposed to be hard, only tough question was 5d on June 2015, although that seems to be universally disliked by everyone on this thread
    Sounds like you've done them all. June 2013/4 (R) may be worth a go.

    FWIW, I quite like Q5(d). So it's not universally disliked.

    (Original post by tazza ma razza)
    quick qn about the pmcc and srcc

    do we find sxy and sxx of the ranks or the actual data? I assume ranks cos there would be no point of making it (a+b)/2 would it... so would i be right in saying we would do sxy etc with ranks???
    Yep!
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    (Original post by JoshC98)
    Hardest S3 papers? Have done June 2015, June 2015 IAL and June 2013R which were supposed to be hard, only tough question was 5d on June 2015, although that seems to be universally disliked by everyone on this thread
    I have scores of 68+ on all papers bar the june 15, which I got 59/75... And tbh, all papers before are the same.
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    actually, you know what, the worst qns are the 1 or 2 markers that ask you random bullcrap as it is either right or wrong

    eg/

    The estimates of the standard error of the mean for the staff and for the children are 5.11 and 1.10 respectively.
    (d) Comment on these values with reference to your answer to part (c) and give a reason for any differences
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    (Original post by Zacken)
    Sounds like you've done them all. June 2013/4 (R) may be worth a go.

    FWIW, I quite like Q5(d). So it's not universally disliked.



    Yep!
    It was an interesting question tbf, unlike most of the s3 syllabus. Pretty annoyed I mucked it up tbh.

    Quick question, in what circumstances would you use the pmcc over the spearman rank and vice versa? Feel like I might have seen it be asked before
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    (Original post by JoshC98)
    Quick question, in what circumstances would you use the pmcc over the spearman rank and vice versa? Feel like I might have seen it be asked before
    You'd use the pmcc in the rare cases when there are tied ranks and spearman in the very frequent case where the observed data isn't distributed bivariate normally or where there is non-linear correlation.
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    Zacken

    7.c
    https://869d950bf149eefd5cd2652b4001...%20Edexcel.pdf

    If you work it out by working out this: p(L-T<0.1) - p(L-T<-0.1)
    You get a correct answer.
    But if you do 2p(L-T<0.1)-1 you get it wrong?

    I must've made a mistake somewhere, would like some help
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    (Original post by Zacken)
    You'd use the pmcc in the rare cases when there are tied ranks and spearman in the very frequent case where the observed data isn't distributed bivariate normally or where there is non-linear correlation.
    Thanks a lot! Not allowed to give you any more rep it seems
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    It does for continuity corrections
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    Anyone have a link to the 2015 IAL paper?
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    (Original post by cjlh)
    Anyone have a link to the 2015 IAL paper?
    On the Edexcel website.
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    (Original post by Armpits)
    Zacken

    7.c
    https://869d950bf149eefd5cd2652b4001...%20Edexcel.pdf

    If you work it out by working out this: p(L-T<0.1) - p(L-T<-0.1)
    You get a correct answer.
    But if you do 2p(L-T<0.1)-1 you get it wrong?

    I must've made a mistake somewhere, would like some help
    second that! what is the difference with that question, and this one 8a

    https://869d950bf149eefd5cd2652b4001...%20Edexcel.pdf
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    (Original post by Armpits)
    Zacken

    7.c
    https://869d950bf149eefd5cd2652b4001...%20Edexcel.pdf

    If you work it out by working out this: p(L-T<0.1) - p(L-T<-0.1)
    You get a correct answer.
    But if you do 2p(L-T<0.1)-1 you get it wrong?

    I must've made a mistake somewhere, would like some help
    The expression you have 2P(L-T &lt; 0.1) - 1 only works if E(L-T) = 0 so we can use the symmetry of the normal distribution curve. This doesn't hold here, so you can't use that method.
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    (Original post by kennz)
    second that! what is the difference with that question, and this one 8a

    https://869d950bf149eefd5cd2652b4001...%20Edexcel.pdf
    As above, see my post. In your question, the expected value of the difference is 0\, allowing us to use the symmetry and get to the expression, this is not true for the other question.
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    (Original post by Zacken)
    As above, see my post. In your question, the expected value of the difference is 0\, allowing us to use the symmetry and get to the expression, this is not true for the other question.
    Got it, thanks you
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    BTW, if anybody gets their hand on the S3 UK/IAL papers after the exam, send them over to me, I might do model solutions if there's demand.
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    (Original post by tazza ma razza)
    actually, you know what, the worst qns are the 1 or 2 markers that ask you random bullcrap as it is either right or wrong

    eg/

    The estimates of the standard error of the mean for the staff and for the children are 5.11 and 1.10 respectively.
    (d) Comment on these values with reference to your answer to part (c) and give a reason for any differences
    the worst questions are the **** about ads/disads of different sampling, feel like im back in business studies
 
 
 
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