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    I just can't get my head round these type of questions!I don't even know where to start!




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    Please could you explain in layman's terms as I will find it simpler
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    That Sigma sign means the sum of. So you know the sum of all the values and you know how many values you have so the mean should be OK to compute.

    There is a formula for sd that uses (sum x^2) and (sum x)^2 and you have those two values too.

    After that I'm no help.
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    Thanks man,
    I understand sigma and that the mean is just Sig(x) /80 I dont have a clue how to get the variance from just them 3 values!
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    I have a formula

    s = sqrt((1/(n-1)x(sum (x^2) - ((sum x)^2)/n)

    What board are you doing and do you have a formula book.
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    AQA Stats1B and yeah got a formular booklet,thats abit baffling what you just wrote :')
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    I'm doing AQA too. Was that question on a past paper or in a text book? The formula that I gave isn't in the formula book so if it was a past paper question I'm shot too 'cos I can't quote it from memory.

    Unfortunately I don't know how to use the latex thing for writing formula on TSR. I'll see if I can find it somewhere else.
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    My stats teacher gave us a bunch of past questions but it doesnt say which paper its from, I'm quite nervous about tomorrow I managed C1 and C2 well but Stats could ruin it all!
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    Here we go. The formula that I was trying to show you can be found here.


    http://wps.aw.com/wps/media/objects/...2/formulas.pdf


    Good luck tomorrow. I'm doing it too. I don't have any expectations except to expect that I won't do very well. Statistics is mumbo jumbo to me. Pure Maths is beautiful but stats YUK
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    Haha same to you thanks for your help looks like we're pretty much in the same boat
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    Yep. Same boat indeed.

    Glad to have helped. I don't think we need to know that formula (famous last words). I think I learn it then it won't come up then we'll both have a better chance. Hahahahaha
 
 
 
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