All Questions
Tagged with sas mixed-model
102
questions
3
votes
0
answers
174
views
Difference in SAS PROC MIXED between DF when using type VC vs FA0(1) for one random effect model
I don't understand why the degrees of freedom (DF) are different between TYPE=VC and ...
- 1,200
13
votes
2
answers
490
views
Beyond AR(1) as a covariance structure for mixed models with repeated measures
I have been reading about alternatives to assuming an AR(1) covariance structure for mixed models with repeated measures (in time). In particular I have heard about Toeplitz and Ante-dependence ...
- 304
4
votes
1
answer
170
views
Doubts about mixed model (R vs SAS) with nested random effects [closed]
I use SAS to fit a simple mixed model where there is nested random effects of Block within Location like this:
...
2
votes
0
answers
40
views
How to solve MME [closed]
I have spent an entire day trying to figure out how to solve these mixed model equations without any luck. I am therefore reaching out to this community. The assignment is as follows:
Using the ...
- 21
6
votes
1
answer
135
views
Understanding SAS Mixed Model Syntax
I'm used to specifying mixed models with mathematical notation or in R using the lme4 syntax. Now, I was asked to review a mixed model fitted in SAS. The SAS model ...
- 683
0
votes
0
answers
19
views
Analyzing discrete Proportional Data with different sample sizes in GLMM?
I am reaching out to seek guidance regarding an issue that has been troubling me for a while.
In my study, I had participants choose a strategy for expressing 6 different emotions across * 5 social ...
- 1
5
votes
1
answer
229
views
SAS Proc Mixed Repeated VS Random (or Both)?
I have data from a study for a "device". Subjects receive an implant and are followed for 5 years, with a checkup every year. A "disability score" is calculated from a survey every ...
- 51
0
votes
1
answer
1k
views
Mixed model for repeated measures with different timepoints and intervals
is there a way to design a mixed model for uneven number of measurements per subject and (more importantly) with uneven time intervals between measurements which are taken at different time points (...
- 23
1
vote
0
answers
62
views
converting proc mixed to R [closed]
I have been trying to convert some PROC MIXED SAS code into R, but without success. The code is:
...
- 171
2
votes
0
answers
56
views
Linear mixed model with repeated measures at two timescales
I want to use a Linear Mixed Model on the following design: 20 subjects with one between-subjects factor (10 males, 10 females). Each subject is measured at 4 timepoints: At 0 weeks, 2 weeks, 4 ...
1
vote
0
answers
32
views
Do you still need to include "site" as a random effect when modeling matched data set?
I am working on a multicenter propensity matched cohort study. The primary outcome is binary while the secondary outcome is continuous. First I performed multiple imputation to address the missing ...
- 15
1
vote
1
answer
156
views
Mixed model without fixed intercept- Numerator df for Type II and III ANOVA (lmerTest vs Proc Mixed)
It comes to my attention that there is a discrepancy between lmerTest and Proc Mixed for the numerator degrees of freedom (df) for type II and III ANOVA. This only occurs for mixed model without fixed ...
- 270
2
votes
0
answers
368
views
Reconciling differences in CI calculated between SAS and R on same dataset
I have been given a brief of replicating statistical analysis which was done previously to verify results. Data being collected are body weights of male and female mice over 20 weeks, given a ...
- 587
1
vote
0
answers
240
views
lmer (R) and proc mixed (SAS)
Recently I have been working on replicating the results from package lmer in R to proc mixed in SAS for mixed modeling. There are multiple model structures that you ...
- 11
3
votes
1
answer
328
views
glmer (R) versus SAS output random effects
I have a binomial glmm model which I have analysed in both SAS and R. However, I have noticed a difference in the statistics which are given for the random effect. In SAS, there is a table called '...
- 111