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Thread: Confused about my Logistic Regression output (SPSS)

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    Confused about my Logistic Regression output (SPSS)




    Hi Guys,

    I've conducted a binary logistic regression using 2 categorical predictors (Static-moving and moving-static) and an outcome variable (M_FASTER).
    When i look at the SPSS output, i see that my model for static-moving is significant (.039):



    However, when I run the same analysis using only 1 predictor (moving-static), I get the same result (apart from the inverse beta coefficient):



    I'm at a loss to really explain why; do you think it is an issue with how I have coded my variables?
    I realise my post may not make alot of sense to people, so please let me know what further information you need.

    Thanks for reading.

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    Re: Confused about my Logistic Regression output (SPSS)

    It seems like it is likely the exact same variable except the 0s and 1s are flipped or the program is grabbing the wrong group as the reference category. There is always the bizarre chance that these two variable are the exact opposites of each other (just by chance) or just the flipped groups (e.g., male, if male they are given a 1; female, if female they are given a 1).


    What were you expecting???
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    Re: Confused about my Logistic Regression output (SPSS)

    Hi, thanks for your reply.

    I was expecting the MovingStatic predictor to not give a significant result.
    Basically, StaticMoving and MovingStatic are 2 conditions of an experiment, and M_faster is a dependent variable. I was expecting a significant regression model for M_faster in the staticMoving condition, but not in the MovingStatic condition. Not sure if that clears it up at all. There are only 16 individuals in each condition, so I can count the number of responses if that would help?

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    Re: Confused about my Logistic Regression output (SPSS)

    Count them and put them in a table. If they are not the complement of each other you may be able to put them both in the model.
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    Re: Confused about my Logistic Regression output (SPSS)


    Ah I think I understand now - I realised they are the complete compliment of one another:



    So i think I'm in the clear now as to what it shows.

    Many thanks for your help.

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