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    If the table is like

    Year: 1993 1994 1995
    Consumption: 35.5 37.7 41.5

    when I make the product moment correlation table, is x:
    1993 1994 1995... etc

    or 3 4 5 ? or something else?

    because when I solve r, the numbers are so big because of the (year) dates and makes my Sxx negative so my result is wrong.
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    (Original post by 0utdoorz)
    If the table is like

    Year: 1993 1994 1995
    Consumption: 35.5 37.7 41.5

    when I make the product moment correlation table, is x:
    1993 1994 1995... etc

    or 3 4 5 ? or something else?
    Either would do.

    because when I solve r, the numbers are so big because of the (year) dates and makes my Sxx negative so my result is wrong.
    Post working.
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    (Original post by ghostwalker)
    Either would do.



    Post working.
    original table:

    year: 1993 1994 1995 1996 1997 1998 1999 2000
    consumption: 35.5 37.7 41.5 46.4 44.8 45.8 53.9 62

    I did a product moment correlation table

    x
    1993
    1994
    1995
    1996
    1997
    1998
    1999
    2000

    y
    35.5
    37.7
    41.5
    46.4
    44.8
    45.8
    53.9
    62

    x^2
    3972049
    3976036
    3980025
    3984016
    3988009
    3992004
    3996001
    4000000

    y^2
    1260.25
    1421.29
    1722.25
    2152.96
    2007.04
    2097.64
    2905.21
    3844

    xy
    70751.5
    75173.8
    82792.5
    92614.4
    89465.6
    91508.4
    107746.1
    124000

    total x: 15972
    total y: 367.6
    total x^2: 31888140
    total y^2: 17410.64
    xy: 734052.3

    sample x mean= 15972/8 = 1996.5
    sample y mean = 367.6/8=45.95

    sxx= 31888140-(8)(1996.5^2)= -28699958
    syy= 17410.64-(8)(45.95^2)= 519.42

    sxy = 734052.3-(8)(1996.5)(45.95)= 138.9

    r= 138.9/ (sqrt(-28699958 * 519.42))

    You can't sqrt a minus number!
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    When calculating Sxx and Syy, its dividing by 8, not multiplying...

    sxx= 31888140-(1/8)(1996.5^2)= ???
    syy= 17410.64-(1/8)(45.95^2)= ???

    Double check your formulas
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    (Original post by Dalilsp)
    When calculating Sxx and Syy, its dividing by 8, not multiplying...

    sxx= 31888140-(1/8)(1996.5^2)= ???
    syy= 17410.64-(1/8)(45.95^2)= ???

    Double check your formulas

    ooh how comes it's not 8?
    I thought sxx was Ex^2 - (number of values) * sample mean x??
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    Sxx = E(X^2) - E(X)^2/n

    Sorry I don't know how to use the fancy writing :P

    Sxx = basically E(X^2) - (mean)^2
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    I did:

    sxx= 3188140 - (1/8)*(1996.5)^2 = -179411.5313

    syy= 17410.64-(1/8)*(45.95)^2=1476.714688

    sxy= 734052.3-(1/8)(1996.5)(45.95)= 722584.9031

    I still can't find r as sxx is negative so I can't square root it in the product moment correlation coefficient formula
 
 
 
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