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    (Original post by Zacken)
    Generally, if it's not too much trouble, I would do it both ways to make sure my answer is correct. (they amount to the same thing, although a bit of care has to be taken w.r.t decimal places rounding) If it was an annoying calculation where the class was >= 6 and I'd need to look up cumulative crap in the tables, then I'd just add up the previous ones and do total - (sum of previous).
    Actually, that makes sense. Cuz that question I did before (where the mark scheme did the adding up method), I remember it being a class like >=6. So definitely the mark scheme agrees with you. Thanks!
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    (Original post by Geraer1)
    Okay thanks! And in this paper, actually one part of q6 involves pooling two columns together as one of the expected frequencies is below 5 for a contingency table. So it did appear in a paper!
    (Original post by Zacken)
    Yes, June 15. You had to explain why, but you didn't actually have to combine it yourself which was what I was talking about.
    Yeah, someone brought that up yesterday.
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    (Original post by Zacken)
    Yeah, someone brought that up yesterday.
    Ah okay!
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    (Original post by Music With Rocks)
    Is there ever a time in S3 when you would use the σ2rather than S2 formula?
    What is the σ2 formula?
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    Quick question:

    You must combine classes for continuous uniform if E is less than 5, right?

    (I know that the same goes for all other chi-sqaured tests)
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    (Original post by zaybun)
    When they ask you to calculate the biased variance as opposed to the unbiased one I'm guessing.
    Anything can be a biased estimator of variance.

    (Original post by Rkai01)
    Could we actually be asked to calculate c in a pdf and those type questions?

    I can't remember much of those s2 things
    Yes, they certainly could but most likely wouldn't given the repetitive nature/style of S3 past papers.
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    (Original post by physicsmaths)
    +-0.6mm so the modulus of the difference.
    This is very known and comes up tonnes go over it in the book.
    when was that paper?
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    (Original post by zaybun)
    Quick question:

    You must combine classes for continuous uniform if E is less than 5, right?

    (I know that the same goes for all other chi-sqaured tests)
    Yes.
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    (Original post by Zacken)
    Yes.
    Thank you! Teacher did an example months back and I just had a look through my notes and I guess she forgot to combine the classes
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    (Original post by tazza ma razza)
    when was that paper?
    2011 or 2010 not sure.


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    (Original post by physicsmaths)
    2011 or 2010 not sure.


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    (Y)
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    (Original post by tazza ma razza)
    when was that paper?
    June 2010, iirc.

    (Original post by zaybun)
    Thank you! Teacher did an example months back and I just had a look through my notes and I guess she forgot to combine the classes
    Yep, must be.
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    Has anyone got a link to last years paper?
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    (Original post by Messier31)
    Has anyone got a link to last years paper?
    Check the Edexcel website
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    (Original post by Messier31)
    Has anyone got a link to last years paper?
    Im about to do that one aswell.
    Report back in abit.


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    (Original post by tazza ma razza)
    (Y)
    ?


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    (Original post by Euclidean)
    Check the Edexcel website
    Oh

    Thanks

    (Original post by physicsmaths)
    Im about to do that one aswell.
    Report back in abit.


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    I'll be expecting you in about half an hour :lol:
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    Community Assistant
    *thumbs up*
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    (Y) is a thumbs up emoji, probably not what you think
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    (Original post by Euclidean)
    (Y) is a thumbs up emoji, probably not what you think
    My thoughts exactly when I first came across it. :mmm:
 
 
 
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