mixed

1. two-way mixed effects models

I am trying to run a mixed effect model defined as: log(volume) = A + B*time + epsilon and A = A0 + A1*T + epsilonA B = B0 + B1*T + epsilonB The data is tumor volumes in two groups (T = 0 or T = 1) of mice, and each mouse's log(volume) increases linearly in time, but with slopes and...
2. Linear Mixed Model not displaying values in Fixed Effects table

I am running a linear mixed model for a repeated measures design, because of some missing data, with several fixed effects and a subject random effect. I am testing several different covariance structures for the repeated measures, and in some cases there are values missing (i.e. DoF and...
3. Proc Mixed effect interpretation

Hello, I am analyzing an experiment in which we tested the effect of different treatments on trauma. So, for example, blood pressure (and other parameters) is followed in animals exposed to trauma and treated in different ways. I am using the Proc mixed procedure to analyze my data with...
4. MIXED model syntax - simple main effects

Hi! I am running a mixed effects models in spss and have found a significant interaction between session and sex. I now wants to examine the simple effects for sex and I've been trying the below syntax but keeping getting the following warning message: "The symbol sex was found following...
5. Mixed model with time-varying covariate - are correlations between covariates bad?

Hi everyone, I have a question regarding the correlation between predictors in a model, and whether I should worry about it in my specific case. Any help would be great. Here are the details: I am interested in the effect of within-subjects treatment Z (two levels) on my dependent variable...
6. Should I handle this as a within-subjects, between-subjects or a mixed design?

My design has two dependent variables (likeability and persuasive power). The independent variable is advertisement version, with 2 levels (individualistic and collectivistic). The participants of the questionnaire each saw 4 different advertisements. These 4 advertisements were either...
7. SPSS GENLINMIXED for non-nested structure

Dear experts, thank you for any help you might offer. I have data in which the groupings are crossed, not nested. Each player responds to the same set of items. In MIXED, I give a separate intercept to each player and to each item -- but not to each combination of these -- using two...
8. Mixed Model ANOVA Error terms

Can someone show me, or point me to a resource, that would show how to compute the resulting Error sums of squares that would be produced in a repeated-measures ANOVA *without* using the typical (SSTotal - (SS Subjects + SS Effect)) subtraction process? I realize the term represents the...
9. overal test differ from lsmeans/pdiff results

Hi all, I run proc mixed and I am not sure how to explain the following results... I am interested in starch content in 3 parts of the same plant (leaves, roots, husks). I am interested in the effect of one factor (3 levels) on starch content in the entire plant and individual parts...
10. Different results from SAS Proc Mixed and SPSS Mixed

I'm running some analyses where SPSS and SAS are giving me different results (i.e., significant here, but not there). I'm attaching the output. I've mostly fiddled with the SAS syntax to match the SPSS results. I've tried adding the covariates to the class statement, removing the random...
11. Split File for Mixed Measures

This is a rookie question, so I apologize in advance - I am doing a mixed ANOVA with 2 levels of within groups (Time) and 2 levels of between groups (Intervention status - control or intervention). I got significant main effects as well as a significant interaction effect. Given that there...