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Edexcel S2 - 27th June 2016 AM Watch

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    (Original post by kosvengali)
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    Could someone quickly explain to me how to solve 4c Jan 2013?
    If -3 < X - 5 < 3 then a < X < b where a =... and b =....
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    (Original post by SeanFM)
    Correct (though if you sketch the half of the distribution that you do know, it may help to..save some integrating, is all I will say).


    Perhaps something is going wrong in the calculation or writing things down?
    I've tried a lot here - can't seem to get an integer for K?
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    (Original post by iMacJack)
    I've tried a lot here - can't seem to get an integer for K?
    Working, please. Otherwise I'm not sure how to help. I wouldn't put it past me to have made a mistake in the question but I've checked a few times, so I'm not sure :erm:
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    (Original post by r3h4f)
    I would have thought that it would be P(X<=8) because CR is X>=9?
    can u explain how please? i dont get the entire question
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    Name:  Screen Shot 2016-06-26 at 14.37.56.png
Views: 83
Size:  121.8 KBSorry i know this question has already been asked, but i just tried doing it myself and I'm a bit confused, its from June 2010.

    Basically i worked out that:
    2x+2y=20
    and because your trying to find P(Y>6)
    P(10-x>6) so therefore
    P(X<4) = 1/2 but why isn't this the answer? why do you have to add on a 1/6 as the answer is 2/3 ??
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    (Original post by SeanFM)
    Working, please. Otherwise I'm not sure how to help. I wouldn't put it past me to have made a mistake in the question but I've checked a few times, so I'm not sure :erm:
    Here's my integration method Name:  ImageUploadedByStudent Room1466948596.711281.jpg
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Size:  133.6 KB


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    how do you go about solving
    d^4-8d^2+8=0

    it was on the june 2014(r) paper
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    (Original post by Lilly1234567890)
    how do you go about solving
    d^4-8d^2+8=0

    it was on the june 2014(r) paper
    Substitute.

    Let y = d^2
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    I dont get what theyve done in Q3b June 2013
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    I also dont get questions with Var like Var(3-2X)

    E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
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    (Original post by fpmaniac)
    I also dont get questions with Var like Var(3-2X)

    E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
    Var(3-2X) = 4Var(X)
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    anybody got links to jan 16 ial?
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    (Original post by fpmaniac)
    I also dont get questions with Var like Var(3-2X)

    E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
    Varx = 9b^2/12

    var(3-2x) = 4Var(x) = 36b^2/12 = 3b^2?
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    (Original post by fpmaniac)
    I also dont get questions with Var like Var(3-2X)

    E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
    Did you do s1? Because you square the number in front of the X and times Var(X) by it. To work out VarX of a uniform distribution use the formula book
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    (Original post by fpmaniac)
    I also dont get questions with Var like Var(3-2X)

    E.g. If uniform dist. has intervals (b,4b) Find Var(3-2X)
    a^2Var(X)

    Then for continuouse uniform distribution Var(X)=((b-a)^2)/12

    I think lol
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    (Original post by iMacJack)
    Add five to both sides of the inequality and work it out? Take care of the 8 in the inequality though, as the maximum value is 6, so adjust the inequality taking note of this
    Thank you!!? ^^

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    (Original post by iMacJack)
    Varx = 9b^2/12

    var(3-2x) = 4Var(x) = 36b^2/12 = 3b^2?
    (Original post by Dentistry101)
    Did you do s1? Because you square the number in front of the X and times Var(X) by it. To work out VarX of a uniform distribution use the formula book
    Thanks. And I didnt do S1
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    Name:  Uniform Distribution.png
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Size:  95.2 KB

    How do you do part (c) (d) and (e) ?
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    (Original post by SeanFM)
    If -3 < X - 5 < 3 then a < X < b where a =... and b =....
    Thank you

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    (Original post by NotNotBatman)
    Name:  Uniform Distribution.png
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    How do you do part (c) (d) and (e) ?
    How do you find R in terms of X?

    (Hint: it is the area of a rectangle with one length being ... and the other ...)
 
 
 
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