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    Even though S3 is over, I thought I'd share an interesting expectation algebra question from the IAL paper with everyone.

    I think the question went something like this:

    Given that \mathrm{E\left ( S^{2} \right )} is an unbiased estimator of \sigma^{2}, and the data obtained is from a population with mean \mu and variance \sigma^{2}, show that \displaystyle \mathrm{Y = \frac{1}{8}\left ( \sum_{i=1}^{8}X_{i}^{2}-8\bar{X}^{2} \right )} is a biased estimator of \sigma^{2}.

    Krollo, physicsmaths - you guys might like this.
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    (Original post by Krollo)
    Weird thing is, I would probably be a lot less stressed about exams if I knew I'd dropped marks already... at the moment it seems teachers / friends / folk online are kind of expecting me to get full ums again when I know it isn't realistically possible. Knowing that I've already dropped marks can make things much easier, since beyond that A Levels serve little real purpose for me provided I don't completely **** them up.

    My brain is a strange place, sorry for pouring it out onto the s3 thread guys

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    I know what you mean but except people expect me to get kill every module(not 100 but like 90+) little do they know I always do the bare minimum to get the grade needed like in D2 i will learn one chapter to get the 10 ums i need. I hate maths modules tbh, i don't have consistency even in FP and mechanics to get straight raw 100s due to not paying enough attention to mark schemes.


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    (Original post by Krollo)
    Weird thing is, I would probably be a lot less stressed about exams if I knew I'd dropped marks already... at the moment it seems teachers / friends / folk online are kind of expecting me to get full ums again when I know it isn't realistically possible. Knowing that I've already dropped marks can make things much easier, since beyond that A Levels serve little real purpose for me provided I don't completely **** them up.

    My brain is a strange place, sorry for pouring it out onto the s3 thread guys

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    S'alright mate, just work your ass off for meeting your offer and nobody is going to care about UMS. You're already meme-worthy. :lol:
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    (Original post by Ayman!)
    Even though S3 is over, I thought I'd share an interesting expectation algebra question from the IAL paper with everyone.

    I think the question went something like this:

    Given that \mathrm{E\left ( S^{2} \right )} is an unbiased estimator of \sigma^{2}, and the data obtained is from a population with mean \mu and variance \sigma^{2}, show that \displaystyle \mathrm{Y = \frac{1}{8}\left ( \sum_{i=1}^{8}X_{i}^{2}-8\bar{X}^{2} \right )} is a biased estimator of \sigma^{2}.

    Krollo, physicsmaths - you guys might like this.
    Biased or unbiased?
    Where have i gone rong
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    (Original post by Ayman!)
    Even though S3 is over, I thought I'd share an interesting expectation algebra question from the IAL paper with everyone.

    I think the question went something like this:

    Given that \mathrm{E\left ( S^{2} \right )} is an unbiased estimator of \sigma^{2}, and the data obtained is from a population with mean \mu and variance \sigma^{2}, show that \displaystyle \mathrm{Y = \frac{1}{8}\left ( \sum_{i=1}^{8}X_{i}^{2}-8\bar{X}^{2} \right )} is a biased estimator of \sigma^{2}.

    Krollo, physicsmaths - you guys might like this.
    Looks interesting. Before I get started is the 8xbar^2 within the summation, if you see what I mean?
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    (Original post by Krollo)
    Looks interesting. Before I get started is the 8xbar^2 within the summation, if you see what I mean?
    Nope.

    Don't get too interested, it's only 2 marks.
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    (Original post by Zacken)
    Nope.

    Don't get too interested, it's only 2 marks.
    Did i get it rite


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    (Original post by physicsmaths)
    Did i get it rite


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    Nah.
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    (Original post by Zacken)
    Nah.
    Fukin statistics. ********, the question is rong thats y. Mandem is sick


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    Remember that if S^2 is an unbiased estimator of \sigma^2 then 7S^2 = \sum_{i=1}^8 X_i - 8\bar{X}
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    Worded the question slightly wrong; E(S^2) = sigma^2. :ninja:
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    Dis questions bare hard.
    Man is baffed bruv.
    Gna go do some step ii stats to make myself feel gud


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    S3 model solutions here
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    This is late... oh well

    what are we thinking boundaries are for this paper (A*-B) almost certain i got 65+ and am hoping it is at least 80 ums. Thanks
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    (Original post by tazza ma razza)
    This is late... oh well

    what are we thinking boundaries are for this paper (A*-B) almost certain i got 65+ and am hoping it is at least 80 ums. Thanks
    A* probably 70. B around 55-57?


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    (Original post by physicsmaths)
    A* probably 70. B around 55-57?


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    A would be 62ish then yh?
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    (Original post by tazza ma razza)
    A would be 62ish then yh?
    But higher 64 id say and 57 a B and 70 the A*.


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    How much UMS for 66/75
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    Anyone's opinion would be appreciated
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    (Original post by Honey badger123)
    Anyone's opinion would be appreciated
    wait until 11th august.
 
 
 
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