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  4. Day 8: Pearson Correlation Coefficient II
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Day 8: Pearson Correlation Coefficient II

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  • sabsfilho
    1 month ago+ 0 comments
    b = p * (stdDevX / stdDevY)
    
    Y = b * X + a
    
    1) y = -3x/4 - 2 => b1 = -3/4
    
    2) x = -3y/4 - 7/4 => b2 = -3/4
    
    b1 = p * (stdDevX / stdDevY)
    b2 = p * (stdDevY / stdDevX)
    k = (stdDevX / stdDevY)
    
    b1 = p * k => p = b1 / k
    b2 = p / k => 1/k = b2 / p
    p = b1 * b2 / p => p*p = b1 * b2
    p*p = (-3/4) * (-3/4) = 9/16
    p = 3/4
    
    b1 and b2 are negative, 
    so Pearson Coefficient is -3/4
    
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  • panchaly75
    4 months ago+ 0 comments

    https://www.sarthaks.com/830322/from-the-equations-of-the-two-regression-lines-4x-3y-7-0-and-3x-4y-8-0-find-a-mean-of-x-and-y

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  • SEND_VCON
    1 year ago+ 0 comments

    In a simple linear regression with 1 independent variable 'x', B1 (coefficient of x in the regression equation) is equal to

    r(stdx/stdy)

    where r is the Pearson correlation coefficient.

    So given that B1 is the same for both regression equations, we know that the ratio stdx/stdy must be the same, since r is the same value in both equations. (r is the correlation between x and y). And then as a direct result, we get r = B1.

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  • mitchell_carroll
    2 years ago+ 0 comments

    I would like to complete the 10 days of statistics, but I am locked out from reattempting the multiple choice question. I got the question wrong on my first attempt and then frustratingly guessed the answer knowing that my odds of correctly guessing the answer within the allotted number of guesses were 5/6. Unfortunately, I guessed wrong everytime. I know guessing is not the way to go and would like the challenge to be reset if possible. I can't stand having this challenge hanging at 96% on my front page. What can I do?!

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  • jerlich
    2 years ago+ 0 comments

    By rearranging the equations we can see that y ~-x. So that eliminates all the positive choices. Correlation is on the range [-1 1] so we can eliminate -4/3 and they are not perfectly correlated (because then the two equations would be equal). So by elimination the answer must be the one that is negative and >-1

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