```Date: Wed, 15 Apr 1998 15:41:30 -0600 Reply-To: mgonen@ALOGIC.COM Sender: "SAS(r) Discussion" From: mgonen@ALOGIC.COM Organization: Deja News - The Leader in Internet Discussion Subject: Re: Analysis of Covariance with Repeated Measures In article <6gtj1l\$f9o\$1@flood.weeg.uiowa.edu>, chuck@barney.pmeh.uiowa.edu wrote: > > Someone recently asked me a question about the repeated measures > analysis of covariance example on pp. 805-808 of Winer, 1971, > Statistical Principles in Experimental Design. > > The example has three groups with three subjects/group. A response > (Y) and a covariate (X) are measured two times for each subject. > Neither one of us can determine how to produce Winer's analysis of > covariance (panel (iii) of Table 10.6-7). > > It seems evident that the "multivariate" data organization of proc glm > can't be used, since there's no way to account for the repeated > measurements of the covariate. The "univariate" data organization > gives some of Winer's sums of squares, but doesn't give Winer's > estimate for the group sum of squares (factor A). > > Although I'm not an SPSS user, the person who asked me the question is > able to reproduce Winer's results using SPSS. > > If anyone in this group has previously considered this type of > example, I'd appreciate your comments. > > Thanks, > > Chuck > > The SAS statements I've considered follow: > > data covar; > input subject group time x y; > cards; > 1 1 1 3 8 > 1 1 2 4 14 > 2 1 1 5 11 > 2 1 2 9 18 > 3 1 1 11 16 > 3 1 2 14 22 > 4 2 1 2 6 > 4 2 2 1 8 > 5 2 1 8 12 > 5 2 2 9 14 > 6 2 1 10 9 > 6 2 2 9 10 > 7 3 1 7 10 > 7 3 2 4 10 > 8 3 1 8 14 > 8 3 2 10 18 > 9 3 1 9 15 > 9 3 2 12 22 > ; > proc glm; class subject group time; > model y=group subject(group) time group*time x; > test H=group E=subject(group); > > You can use PROC MIXED to work with univariate repeated measures. Check documentation for Release 6.11 for a comprehensive account of different covariance structures it offers. Mithat Gonen mgonen@alogic.com -----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/ Now offering spam-free web-based newsreading ```

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