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I have two different terms contributing to a sum. One is positive and one is negative(-0.077 and 0.067) How do I note the contribution of these terms in percentage? 0.067/(-0.01) -> -670% doesn't make any sense.

Edit: I know that logically 0.067 is -670% of the sum but I need to measure the relative weight of a term in a sum. Is comparing the absolute values a way to do it?(i.e 0.067/(0.067+0.077))

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You could do it in terms of absolute values; in that case, the 'total' is 0.077 + 0.067, and the the contribution of the positive part is 0.067/(0.077 + 0.067) = 46,5 %. –  Gerben May 3 '11 at 11:50

1 Answer 1

If you are willing to say that, in the sum $(-6)+(-4)=-10$, the minus six contributes 60% of the sum and the minus four 40%, then logically you should be prepared to say that, in the sum $(-0.077)+0.067=-0.1$, the $-0.077$ contributes 770% and the $+0.067$ contributes -670%.

But it would probably be better not to attempt say anything like this, to avoid confusion.

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This is a good demonstration of the loss of precision caused by subtraction. If you make a small percentage change in one of the summands, you make a large percentage change in the sum. The -670% and 770% figures are one way to represent that. –  Ross Millikan May 3 '11 at 12:54
    
While this is logically true, it is not useful in my case. –  Atilla Filiz May 3 '11 at 14:51

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