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    ok I have a question in this thread http://www.uk-learning.net/t46911.html that also needs to be answered please as I have no clue.

    My second question is if neither x or y variables are controlled, yet you are given both yon x and x on y regression lines. Which one do you use? The answer claims use x on y, if under these circumstances is that always the case?

    Additional info the lines are

    x=1.11 + 1.06y

    y=1.78 + 0.586x

    Use appropriate line to calculate y=3.4 Why is it x on y line??

    muwhaahha after typing all that out i think ive got it, if you need to find x given u know y use x-on-y as x = in terms of y hah! please say im right, or is it not that obvious.
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    I don't really understand what you're saying
    I have my own query though
    i know you use median and IQR when there are extremes of data
    but when is the mean and s.d (i think) better?
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    (Original post by PrincessParadox)
    but when is the mean and s.d (i think) better?
    With large amounts of quantative data that is unlikely to contain extreme values. In reality they will probably give you an idication of which to use.
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    I do believe yes, I think of it this way, if the data has an abnormal result the mean will be accounting for the abnormality. => not as accurate as if one were to use the median. => opposite is the reverse of that.


    Talking Binomial,

    P(2<= x <=4) using tables it be (value)3 - (value)1 correct?

    i understand it when its just P(x>5) or something on its own, but when inbetween its different whats the rule behind this? And is it the same for geometric?
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    thanks guys
    another thing
    how do you draw regression lines? I mean you have a y intercept but the gradient is usually some weird decimal number?
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    (Original post by PrincessParadox)
    thanks guys
    another thing
    how do you draw regression lines? I mean you have a y intercept but the gradient is usually some weird decimal number?
    Either they will give you a grid or u just do a rough sketch!
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    even with a grid... it's stupid to ask you to draw lines with decimal gradients... some things in stats are so tedious!
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    (Original post by PrincessParadox)
    even with a grid... it's stupid to ask you to draw lines with decimal gradients... some things in stats are so tedious!
    Won't you have to plot points and then draw the line of regression?
    using the a +bx formula?
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    yeah you plot a scatter graph right?
    or do you have to manipulate the values using the equation for regression?

    alsoi has anyone done the exam paper at the back of Heinemann S1?
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    (Original post by PrincessParadox)
    yeah you plot a scatter graph right?
    or do you have to manipulate the values using the equation for regression?

    alsoi has anyone done the exam paper at the back of Heinemann S1?
    If you mean the AQa book, i did in the olden days
    manipulation
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    ARGH so you have to put every x value through the regression equation and then plot that? the textbook just confuses me on this aspect (edexcel)
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    (Original post by PrincessParadox)
    ARGH so you have to put every x value through the regression equation and then plot that? the textbook just confuses me on this aspect (edexcel)
    I believe so...that's what i did in my stats paper last year....

    (Original post by PrincessParadox)
    ARGH so you have to put every x value through the regression equation and then plot that? the textbook just confuses me on this aspect (edexcel)

    not EVERY x value.
    Pick a couple.

    It's a good idea to plot & label the point that's the mean of x and the mean of y - the regression line should go through this.

    So if you plot that point, the y-intercept (whcih you know) and one or two more points just to check - sorted.
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    damn you princess uve hijacked my thread and everyones answered ur questions and not my binomial one!

    Edit: Sorted Now.
 
 
 
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