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    (Original post by tazza ma razza)
    you sure?
    Yup, there's a whole other formula for that, and we are only required to calculate CI for the pop mean.
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    Good luck guys!
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    (Original post by Nikhilm)
    Yup, there's a whole other formula for that, and we are only required to calculate CI for the pop mean.
    ie x bar or mew?
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    (Original post by Nikhilm)
    Yup, there's a whole other formula for that, and we are only required to calculate CI for the pop mean.
    That's what i thought and was really surprised at this question.
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    Q3 part d june 13 R, can someone explain the explanation?
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    (Original post by tazza ma razza)
    ie x bar or mew?
    xx
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    anyone got the 2015 IAL papers ?, i think physicandmathtutor removed it from the website
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    (Original post by economicss)
    Please could anyone clarify when we quote the parameters and n,p etc in hypotheses for goodness of fit and when we don't? Thanks
    (Original post by economicss)
    So if we have to show a probability is 0.3 for example, then we wouldn't include this in the hypotheses and we would just say 'binomial distribution is a suitable fit' but if we were explicitly told 'the teacher thinks the distribution can be modelled by B(20,0.05) for example then we would write B(20,0.05) in the hypotheses, is that right?Thanks
    Yes.

    (Original post by econam)
    Attachment 537351
    Does anyone have any ideas for part c? Much appreciated
    Clearly you need to work out the value of 2\alpha + 3 but earlier on in the question you were asked to find k\bar{X} being an unbiased estimator of \alpha. What is \bar{X} for this sample? What is the unbiased estimator of \alpha, hence, what is 2\alpha +3?
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    (Original post by Nikhilm)
    Mu; Confidence intervals are always for pop parameters, therefore Xbar cannot have a CI (it can have a critical region as in hypothesis tests however)
    sorry, i played and watched too much pokemon as a kid but i get what you mean - thanks for clarification
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    (Original post by Zacken)
    Yes.



    Clearly you need to work out the value of 2\alpha + 3 but earlier on in the question you were asked to find k\bar{X} being an unbiased estimator of \alpha. What is \bar{X} for this sample? What is the unbiased estimator of \alpha, hence, what is 2\alpha +3?
    cooooool you sitting this exam btw big man?
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    (Original post by physicsmaths)
    Q3 part d june 13 R, can someone explain the explanation?
    in part b you found that there is apositive correlation between the population and the number of council employees, therefore if the RANK of population increase, the RANK of employees increase. But in part c, you found that there is not any LINEAR correlation between them, which mean the increase in population does not necessary result in increase in number employees
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    (Original post by anndz3007)
    anyone got the 2015 IAL papers ?, i think physicandmathtutor removed it from the website
    Edexcel website. Go on it, qualifications -> international a-levels -> mathematics -> etc...

    (Original post by physicsmaths)
    Q3 part d june 13 R, can someone explain the explanation?
    From S1, you should know that pmcc tests linear correlation, whereas spearmans tests just correlation, i.e could be quadratically correlated or w/e. So if pmcc fails but spearman works, it means there's a non-linear correlation.

    (Original post by tazza ma razza)
    cooooool you sitting this exam btw big man?
    Yep. IAL, though.
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    (Original post by Zacken)
    Edexcel website. Go on it, qualifications -> international a-levels -> mathematics -> etc...



    From S1, you should know that pmcc tests linear correlation, whereas spearmans tests just correlation, i.e could be quadratically correlated or w/e. So if pmcc fails but spearman works, it means there's a non-linear correlation.



    Yep. IAL, though.
    how do you know which one works and which one fails tho?
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    (Original post by Zacken)
    Edexcel website. Go on it, qualifications -> international a-levels -> mathematics -> etc...



    From S1, you should know that pmcc tests linear correlation, whereas spearmans tests just correlation, i.e could be quadratically correlated or w/e. So if pmcc fails but spearman works, it means there's a non-linear correlation.



    Yep. IAL, though.
    awesome stuff mate you not in the uk then?
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    (Original post by physicsmaths)
    how do you know which one works and which one fails tho?
    Previous two parts. The first part showed you that spearman > 0 from the hypothesis test and the other one showed pmcc = 0 in the hypothesis test.

    So spearman correlation but not pmcc correlation.
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    (Original post by tazza ma razza)
    awesome stuff mate you not in the uk then?
    Naaah, live in Mauritius. I'll see if I can do model answers for the UK S3 paper, though.
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    Name:  Capture d’écran 2016-05-24 à 12.23.04.png
Views: 115
Size:  18.3 KB

    This was in the mark scheme of a chi squared test. Can someone why there is no followthrough?? It makes ZERO sense! Like what if I did a calculation mistake? What does my calculation mistake have to do with my ability to deduce/write a conclusion to a test? WHAT THE HELL IS WRONG WITH EXAM BOARDS??? Like this isn't the first time where they punish you fifteen million marks for small mistakes or mistakes that are unrelated.
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    (Original post by Zacken)
    Yes.


    Clearly you need to work out the value of 2\alpha + 3 but earlier on in the question you were asked to find k\bar{X} being an unbiased estimator of \alpha. What is \bar{X} for this sample? What is the unbiased estimator of \alpha, hence, what is 2\alpha +3?
    Thank you
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    (Original post by Zacken)
    Previous two parts. The first part showed you that spearman > 0 from the hypothesis test and the other one showed pmcc = 0 in the hypothesis test.

    So spearman correlation but not pmcc correlation.
    cheers, q4d on the june 13r paper, what is this? it aint contingency **** so what is it?
    just seeing if it fits something? i got it right but i just guessed it the whole way lol
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    (Original post by gagafacea1)
    Name:  Capture d’écran 2016-05-24 à 12.23.04.png
Views: 115
Size:  18.3 KB

    This was in the mark scheme of a chi squared test. Can someone why there is no followthrough?? It makes ZERO sense! Like what if I did a calculation mistake? What does my calculation mistake have to do with my ability to deduce/write a conclusion to a test? WHAT THE HELL IS WRONG WITH EXAM BOARDS??? Like this isn't the first time where they punish you fifteen million marks for small mistakes or mistakes that are unrelated.
    Which paper?
 
 
 
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