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Thread: SEM Confidence Intervals and Repeated Measures

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    SEM Confidence Intervals and Repeated Measures




    I'm analysing data from a repeated measures study. All of my stats tests (ANOVA and non-parametric tests where appropriate) are telling me that the groups differ but when I plot my graphs my SEM CIs are overlapping. I've always thought this meant the groups did not differ? Do SEM CIs represent something different in within subject designs?

    Thanks!

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    Re: SEM Confidence Intervals and Repeated Measures

    When you say the groups differ, what do they differ on? When you say the SEM CI's overlap, which parameters are you looking at?

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    Re: SEM Confidence Intervals and Repeated Measures

    Quote Originally Posted by CowboyBear View Post
    When you say the groups differ, what do they differ on? When you say the SEM CI's overlap, which parameters are you looking at?
    The differ on group means (as tested by the ANOVA) and medians (for non-parametic tests). When I plot the graphs on both excel and SPSS, I assume that I'm just plotting the SEM CIs of the groups, as attained from each individuals mean.

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    Re: SEM Confidence Intervals and Repeated Measures


    Ahhh... do you mean the confidence intervals based on the Standard Error of the Mean? I thought we were talking Structural Equation Modeling...

    Two sample means can be statistically significantly different to one another, and yet still have overlapping confidence intervals:
    http://amath.colorado.edu/faculty/vd...rlappingCI.pdf

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