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Stat Majors - Help. A Question About Residual Analysis.

Here is my problem which hours on the Internet has yet to resolve. I have a log-log linear regression with just an X and Y, Even with Log-log, the normal prob plot is turned down or up at each end, nice and straight in-between. HOWEVER, the residual plot has a distinctive negative slope where, as X grows, the residual goes from almost total > 0 until it finally goes negative for the larger Xs; the variance seems more or less constant. What is that residual pattern telling me? Does anyone have an idea?

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Randy M. profile image90

Randy McLaughlin (Randy M.) says

3 years ago
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    My Esoteric 3 years ago

    Thanks Randy. While researching for an answer I stumbled across a "Box-Cox Power Transform" method. It seemed to do the trick in straightening out my residual normal plot once I, by trial and error, got to the right "lambda" value for the transform

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