1
vote
1answer
19 views

Correct specification of HLM in lmer

I originally learned about random effects models when taking a course on Hierarchical Linear Models, which was taught using Raudenbush and Bryk's HLM book and software, and it sort of indoctrinated me ...
0
votes
0answers
14 views

Cross-classified HLM (random effects) with lmer in R

I need to run a cross-classified (partially nested / partially crossed) HLM in R using lmer. I haven't found many (any?) clear discussions on how to model this and how to set up the data (besides the ...
2
votes
0answers
49 views

Multiple correlated random non-nested intercepts in R

I am trying to estimate a longitudinal model in R in which there are several random intercepts that are correlated with each other, and the data are non-nested. For example, consider a simple ...
3
votes
1answer
46 views

What is the null model for a likelihood ratio test of a within-subjects factor?

Tissue samples were taken from 4 differention locations and repeatedly measured. This was done identically for 3 animals. The research question was: Are there differences in measurement between the ...
0
votes
1answer
55 views

Random effect significance in linear mixed model

I have performed LRT: ...
2
votes
0answers
126 views

Mixed effect linear regression model output interpretation

I just fitted the following linear mixed effects model: ...
0
votes
1answer
59 views

I am confused with ranef function in R

Do the ranef and fixef functions in lmer give the random and fixed effect coefficients? If ...
1
vote
1answer
63 views

Specifying a linear mixed model in lmer with replications nested within a fully crossed design

I’m trying to specify a linear mixed model for a somewhat complicated, nested & crossed method comparison study with replicated measurements. The goal is to partition and compare variances. It’s ...
0
votes
1answer
74 views

Number of observations in groups - linear mixed effects model

I would like to fit linear mixed effects model to my dataset, but I was wondering if quantity of observations in groups matter? I have some groups with about 60 observations in each, but there are ...
1
vote
0answers
40 views

Multiple covariates for each fixed effect

I'm analyzing data from a classical intervention design. Subjects were divided into groups, undertaking different interventions. Each subject was measured using the same tests before and after the ...
1
vote
1answer
97 views

mixed effects model output

Let's say we have this: ...
1
vote
1answer
71 views

Mixed Model Analysis of Experiment Data using lmer() Function (lme4 package in R) where Levels in Stimulus Grouping Factor equal Observations

I am running a post-hoc analysis on the data collected during an experiment in which 15 unique stimuli were presented to participants. Having run a least squares regression using the lm() function in ...
0
votes
0answers
21 views

Assessing the effect of related variables using lmer in R

I am trying to run a model to describe the rate of water table drawdown in the soil. The predicted variable is rate, and I am interested in the effect of two categorical variables: (1) if the water ...
4
votes
1answer
118 views

Mixed effects modelling; what to do when model is over-specified?

I'm trying to use mixed-effects modelling to analyse some data. There are a number of variables that I need to specify within the model, two of which are between-participants (...
2
votes
1answer
130 views

difference in results of mixed effects model in nlme and lme4 package

Can anyone please tell me why the results of random slope model is different for the same dataset when I use lme and lmer. I first fitted a random intercept model as follows using both lme as well ...
0
votes
0answers
43 views

collinearity in linear mixed effects model

I have one dependent variable (continuous data) and 4 independent data (mix of continuous and count) collected over 35 years across several states. I am using a linear mixed effect models with a ...
0
votes
1answer
73 views

Linear mixed effect models with two independent variables

I am estimating a random intercept and a random slope model using the following R code. My dependent and independent variable are both continuous. ...
1
vote
0answers
38 views

R-squared for linear mixed effects model [duplicate]

I ran linear mixed effects model in R. model<-lmer(yld ~ rain + (1+rain|state),data=data,REML=FALSE) Is there any way I can generate an R-squared for the ...
0
votes
0answers
16 views

difference between mixed effect and a simple ANCOVA

So I have collected data for 50 years of my dependent variable (continuous) data (x), independent (continuous) variable (y) across 10 locations. My null hypothesis is that the regression slopes ...
2
votes
1answer
54 views

Are best linear unbiased predictions (BLUPs) a good indicator of the mean value for that random effect member?

I have data on prices of houses in different districts, and would like to determine how expensive different districts are when it comes to buying a house. However, houses vary with respect to ...
0
votes
0answers
54 views

Help with lmer in the lme4 package

I am new to using linear mixed models and would greatly appreciate any help I can get. I have an equation of the form $ y = X\beta + Zu + \epsilon$ where $u$ is a random effect whose covariance ...
0
votes
0answers
33 views

Mixed modelling with lmer

I've read multiple posts on model fitting using lmer(), but I saw multiple versions of using the error term which made it confusing for me. I have a factorial ...
0
votes
0answers
22 views

Do I need by-item effects in my lmer model, with gain scores as DV?

I'm attempting to fit a relatively straightforward linear model in R, but am in doubt as to whether by-item effects should be included in the model. Any input would be most appreciated! Study design: ...
1
vote
0answers
58 views

In an experiment w/binomial responses, some subjects gave the same answer for all trials. [How] can a Mixed Effects model (R's lmer) deal with this?

I recently ran a pilot of an experiment on Amazon's Mechanical Turk. In the experiment, participants read 5 items, and answered a yes/no question about each one. A between-participants factor was ...
2
votes
1answer
152 views

anova type III test for a GLMM

I am fitting a glmer model in the lme4 R package. I'm looking for an anova table with p-value shown therein, but I cannot find ...
1
vote
0answers
31 views

Should I control for random effects of participant in an individual differences design?

I'm trying to analyse a survey study in which I'm interested in the way that individual differences between my participants influence how they respond to my stimuli. The stimuli are pieces of writing ...
0
votes
0answers
45 views

Estimated SD equal to 0 (lmer)

I'm trying to fit a mixed model of my data, but I'm getting the estimated between-subject standard deviation equal to zero. I need to estimate the between-subject standard deviation and within-subject ...
2
votes
1answer
2k views

Lmer model fails to converge

My data is described here What can cause a "Error() model is singular error" in aov when fitting a repeated measures ANOVA? I am trying to see the effect of an interaction using ...
0
votes
0answers
67 views

Differences between lsmeans and difflsmeans

I've created an lmer model. The effects of one of my treatments, "Fertilizer" varies depending on whether I use lsmeans or ...
4
votes
2answers
186 views

Is my dataset suitable for a mixed effects model?

I've been putting a lot of work over the last few days into bring mixed effects models to bear on some behavioural data I've collected for my thesis, but it's occurred to me that I'm not 100% sure ...
0
votes
0answers
70 views

Specification of a mixed model with nesting with lmer

I've been told my model wasn't statistically correct, but I'm not sure what I should do. What I have is basically 2 species: A and B. For each species, I have 3 replicates: 1, 2, and 3 (=6 ...
0
votes
0answers
57 views

Should I be using a GLMM?

I'm looking at the influence of pollen type on whether a flower sets fruit (i.e., yes or no = 1 or 0). Then looking at number of seeds per fruit (1-6 possible). I was told I should use lmer, however ...
1
vote
0answers
122 views

Repeated measures mixed model using lmer in R

I’m hoping to get some guidance in specifying a mixed model using the lme4 package in R. The study is quite straightforward. It’s a repeated measures design with pre/post measurements on the ...
1
vote
0answers
168 views

lme / lmer - split-plot with Non orthogonal subdesign

I have an agricultural field experiment (testing a plant protection agent): Split plot design with: ...
0
votes
0answers
76 views

Cannot do Tukey test in multcomp

After performing series of linear mixed models in lme4 to justify which model with which level of interaction to be used, now I would like to do the Tukey's test for multiple comparison. So first, I ...
3
votes
0answers
257 views

lmer() parametric bootstrap testing for fixed effects

I am performing a parametric bootstrap to test whether I need a specific fixed effect in my model or not. I have mainly done this for exercise and I am interested if my procedure so far is correct. ...
0
votes
0answers
52 views

Two-way interaction: interpret output from LMM in lmer

I have asked a question in this topic relating interpreting two- and three-way interactions in this link: How to interpret 2-way and 3-way interaction in lmer? ...
0
votes
0answers
44 views

Interpretation of three-way interaction in an output of lmer

I am using lme4 to run a three-way interaction model. I have three independent variables: animal (rat, lion, dog), color (red, green, blue) and sex (male, female). The baselines are as follows: ...
2
votes
2answers
115 views

A good source to understand interaction in LMM?

I would like to know more about interaction in LMM using lmer. Can you recommend me any books, articles, websites?
1
vote
0answers
39 views
0
votes
0answers
32 views

Do I need a planned contrast or post-hoc analysis when doing LMM in R?

I am doing a LMM in R and would like to know if I need to do a planned contrast or a post-hoc analysis. From my understanding, the LMM in R already provideds me a planned contrasts and if I have ...
2
votes
0answers
78 views

Multilevel model specification for count data (with overdispersion) in R

I would like to specify a multilevel model including the following variables: DV: count data, i.e. a score value between 0 and 13 (resulting from an additive index) for each individual Individual ...
2
votes
0answers
48 views

lmer giving worse performance than lm

I am having trouble training a model for nested data about house prices. Lets say my data looks like following: ...
0
votes
0answers
55 views

LMM models with two difference reference categories yield two different results

I have run LMM models with different reference categories and this yield different results: ...
6
votes
1answer
94 views

Notation for multilevel modeling

The formula one needs to specify for training a multilevel model (using lmer from lme4 R ...
5
votes
0answers
324 views

Meaning of a convergence warning in glmer

I am using the glmer function from the lme4 package in R, and I'm using the bobyqa optimizer ...
0
votes
0answers
29 views

Subjects:condition interaction random effect in a growth model

I'm investigating the effect of 'Condition' (3 levels: Quiet, Intelligible, Unintelligible) on pupil response over time (intercept, linear, cubic, quadratic, quartic and quintic terms). When I use ...
0
votes
0answers
78 views

Growth curve analysis on orthogonal polynomial terms

I am conducting a study which is looking at the effect of 'Condition' (Quiet, Intelligible, Unintelligible) on the pupil(eye) response over time. Upon visual inspection of my data plots, pupil ...
0
votes
0answers
48 views

ANOVA in lmerTest for in-between study with repeated measurements

I have a bit of trouble understanding how to formulate a correct formula in R using the lmerTest-library. Let’s assume there is an 2x2 in-between design with repeated measurements. Those repeated ...
0
votes
0answers
125 views

Afex does not give me all p-values of all parameters. What should I do?

I have installed the package afex with this formula: ...