Re: ANOVA Assumption of Independence

Posted by scmesser on Apr 24, 2013; 12:33pm
URL: http://spssx-discussion.165.s1.nabble.com/ANOVA-Assumption-of-Independence-tp5719551p5719682.html

Hi Jignesh.  Good observation.  While I am not an expert in random effects modeling, it sounds like your data structure is consistent with such an analysis.  Essentially you do not have "independent" observations (or errors) since you have observations nested within student nested within teachers.  In other words, your data have an intraclass correlation that should not be ignored (ignoring while bias, sometimes dramatically, ultimately your obtained significance level.  In psychology, the analytic approach used in such data scenarios is often referred to as multilevel modeling (aka in various disciplines with mostly minor differences as random effects models, random regression models, random and/or mixed effects, linear mixed modeling, generalized estimating equations (GEE), etc).  SPSS has the linear mixed models module (and I believe GEE) that I recommend you look into (the linear mixed model vs. GEE may be appropriated depending on whether you utilize a the full exam score, a continuously distributed variable, or the dichotomous pass/fail as your DV).

Others on the List will hopefully shout out my errors in this recommendation?  :)  All the best.