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Edexcel Statistics S1 Exam Jan 2008

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    For the question where you had to find the lower quartile, upper quartile and median.
    Were were supposed to find it out using:
    Q_1 = \frac{n + 1}{4}

    Q_2 = \frac{n + 1}{2}

    Q_3 = \frac{3(n + 1)}{4}

    I remember Q_3 being 258, Q_1 being 171 and Q_2 being 210. Did anyone else get that?
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    ye thats what i got at first but thats coz i typed it into the calculator wrong lol
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    (Original post by TaChYcArDiA)
    yeah whoever posted those E(T) and Var(T) values...I got the same as you whooop!!! That means we got the whole last question correct - whoooop!!!

    Hey erm...what did you guys get for the probability of the complaint for the pop-corn question??? It was really low but I think it was right but I need to know if anyone got the same answer as me...I can't remember the answer...

    oh and for one of the first few questions did you guys get a positive skew for that thing where you had to evaluate the given formula...

    and what method did u lot use to find Q2 ...did you use (n+1)/2 and that gave 6.5th itm and so i averaged 6th and 7th... or simply n/2 and copy the Q2 value...
    yeh
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    and what method did u lot use to find Q2 ...did you use (n+1)/2 and that gave 6.5th itm and so i averaged 6th and 7th... or simply n/2 and copy the Q2 value...[/QUOTE]

    i never averaged the 6th and 7th i just took the 7th value..........:eek: oops
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    (Original post by M.A.H)
    i got -5.88 , we're talking about the Quartiles Q right with the smokers?

    Coz i got 0.155 for Q1 part b/c which is the pmcc
    Lol, was there another question where there was weak correlation? I think I might be talking about question 1 lol
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    (Original post by gj3)
    ye thats what i got at first but thats coz i typed it into the calculator wrong lol
    the -5.88?
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    (Original post by Ar5enal Fan)
    Lol, was there another question where there was weak correlation? I think I might be talking about question 1 lol
    nope only 1
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    eugh i'm really annoyed i never ordered that data. ok i never got a good grade in stats then, heres hoping my C2 and C1 brings it up.
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    (Original post by M.A.H)
    nope only 1
    No I think there was a question about a training program and then the results after one year and you had to evaluate whether or not there had been successful results and as I got a weak correlation I said that it hadn't been a success for the first year.
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    (Original post by Fairy_Pop)
    and what method did u lot use to find Q2 ...did you use (n+1)/2 and that gave 6.5th itm and so i averaged 6th and 7th... or simply n/2 and copy the Q2 value...
    i never averaged the 6th and 7th i just took the 7th value..........:eek: oops[/QUOTE]



    yeah i wasn't sure whether i had to round up the 6.5 to 7th item and simply read it off (which is what i initially done)...or average the 6th and 7th values (which is what i done in the end)...

    but for Q1 and Q3 i simply done 0.25 x 12 and 0.75 x 12 and i read off the 3rd and 9th values...

    does anybody know?
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    i dont understand for the histogram if you got 12 as your final answer then frequency density was 1.2, didnt look anywhere near over one on the graph or was the graph not accurate?
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    (Original post by Ar5enal Fan)
    No I think there was a question about a training program and then the results after one year and you had to evaluate whether or not there had been successful results and as I got a weak correlation I said that it hadn't been a success for the first year.
    yeh for that the pmcc was 0.155 (what i got) i dont think there was another question asking to work out the pmcc
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    For the last bit of Q1, about it being a guide. Something about admissions test...

    Did people work out r = 0.016

    then we had to compare it with the one they gave us r=-0.015, and say whether it was a guide or not..
    I wrote the r value is the same (excluding the positive and negative) so theres not much of a correlation and its not so good for comparing sets of data.

    What did people write?

    edit: I can't remember the exact values of r but they were something like those i used^^
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    the frequency density for the last bar was 0.5 or something...
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    (Original post by TaChYcArDiA)
    i never averaged the 6th and 7th i just took the 7th value..........:eek: oops


    yeah i wasn't sure whether i had to round up the 6.5 to 7th item and simply read it off (which is what i initially done)...or average the 6th and 7th values (which is what i done in the end)...

    but for Q1 and Q3 i simply done 0.25 x 12 and 0.75 x 12 and i read off the 3rd and 9th values...

    does anybody know?[/QUOTE]
    i remember my teacher saying if n is even we can just take the 3rd term or watever, if n is odd then we take the average
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    the pmcc questions were gooood. good old formula booklets
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    (Original post by M.A.H)
    yeh for that the pmcc was 0.155 (what i got) i dont think there was another question asking to work out the pmcc
    Yh, I think i got 0.155 as well
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    (Original post by edward_wells90)
    For the last bit of Q1, about it being a guide. Something about admissions test...

    Did people work out r = 0.016

    then we had to compare it with the one they gave us r=-0.015, and say whether it was a guide or not..
    I wrote the r value is the same (excluding the positive and negative) so theres not much of a correlation and its not so good for comparing sets of data.

    What did people write?
    yeah i got something like that for r. don't remember the rest of that question.
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    (Original post by edward_wells90)
    For the last bit of Q1, about it being a guide. Something about admissions test...

    Did people work out r = 0.016

    then we had to compare it with the one they gave us r=-0.015, and say whether it was a guide or not..
    I wrote the r value is the same (excluding the positive and negative) so theres not much of a correlation and its not so good for comparing sets of data.

    What did people write?

    i never liked that explanation...usually the explanations are easier to write about but they went and introduced a third variable for the discussion which confused me a bit...i wrote bare rubbish for that bit
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    (Original post by edward_wells90)
    For the last bit of Q1, about it being a guide. Something about admissions test...

    Did people work out r = 0.016

    then we had to compare it with the one they gave us r=-0.015, and say whether it was a guide or not..
    I wrote the r value is the same (excluding the positive and negative) so theres not much of a correlation and its not so good for comparing sets of data.

    What did people write?

    edit: I can't remember the exact values of r but they were something like those i used^^
    Yh, I got roughly that value and I basically said the same as you (I think)
Updated: January 31, 2008
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