I want to analyse the data from an experiment.
The participants get different acoustic signals and judge them. The score is a high number, if they feel comfortable with the signal in the other case it is a lower number. I have 5 different signals and 15 participants. The experiment was performed 5 times for each subject, so I've get 65 values.
I want to use a mixed model. I get different results from SPSS and SAS and cannot find the error. It could be that I used PROC MIXED wrong.
proc mixed data=ein1; class Signal ProNr; model se = Signal; random ProNr; repeated /subject=ProNr; run; quit;
The result is:
Die Prozedur MIXED Covariance Parameter Estimates Kov.Parm Subjekt Schätzwert ProNr 0 Residual ProNr 112855 Anpassungsstatistiken -2 Res Log-Likelihood 881.1 AIC (kleiner ist besser) 883.1 AICC (kleiner ist besser) 883.2 BIC (kleiner ist besser) 883.7 Typ 3 Tests der festen Effekte Zähler Nenner Effekt Freiheitsgrade Freiheitsgrade F-Statistik Pr > F Signal 4 48 1.00 0.4169
Did I choose the right parameters? I think that the result says that Signal isn't significant (0.4169 > 0.05). Is this the right interpretation of the results? I used in SPSS an anova with repeated measurements. SPSS corrected the results an the result with greenhouse geisser correction is 0.013. Why this results are so different?
EDIT1: The data looks like:
se Pro_Nr signal 3.4799 1 1 3.3682 2 1 4.3217 3 1 2.9976 4 1 5.5861 5 1 6.7242 6 1 2.6379 7 1 1.9341 8 1
Pro_nr contains values from 1 to 15, every subject get one special number. signal contains numbers from 1 to 5. Each signal gets its own number.
Edit2: Proc glm isn't the right procedure to analyse this data, because no group variable can be defined. I have to use proc mixed for this problem.
Edit3: Is it possible to compare the results of an anova and a mixed model? Did I get the same results with both analyses?
PROC MIXED DATA=ein1; CLASS Frequ ProNr; MODEL se = Frequ; REPEATED / subject=ProNr type=cs; RUN; QUIT;
Did I formulated the model (and so the program code) right to answer the question, wheater se depends on frequ (under the random and repeated effect of subjects)? Do you have some favourite literature to mixed models?