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0answers
24 views

Regarding Nested Anova in R

I would just like to double check if my approach to the following analysis was correct. Based on my design I have two treatments (A and B) with treatment A being comprised of 5 populations and B of 3 ...
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0answers
16 views

standardization within time series and across groups (nested data)

I read through the previous threads concerning standardization of variables, but unfortunately have not found an answer whether it is justifiable or necessary to z-standardize values across groups ...
1
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1answer
63 views

Specifying Cross-Level Interactions in LMER

I am trying to figure out if it's okay to specify cross-level interactions in a hierarchical model with fixed effect predictor variables at both levels using the ...
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0answers
23 views

Correlations of fixed effects in logit mixed model with a nested fixed effect

I am using lme4 in R to fit a logistic mixed effects model of psycholinguistic data with three categorial (binary) fixed effects and two crossed random factors (subjects; items). The critical ...
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0answers
8 views

Age-at-event-stratified analysis for different case-control designs

My question is whether you can perform age-at-event-stratified analyses for: cumulative case-control studies (controls sampled at end-of-study) nested case-control studies (incidence density sampled ...
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0answers
8 views

Tree classifier or nested model?

I am new to statistics and was wondering what the right kind of model to use for the following scenario. I have two sets of continuous observations A and B for 50 samples. These 50 samples are ...
1
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1answer
90 views

Include nesting factor as fixed effect in a GLMM

I have the following GLMM: success ~ age + gender + group/task + (1 + group/task|school/subject), family = binomial I want to know whether participants' ...
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0answers
37 views

Triple nested cross validation

I have read several very informative posts including the link about the nested/double cross validation, which can determine (sub)optimal hyperparameter values as well as make an unbiased estimate of ...
1
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0answers
72 views

including interactions in a mixed linear model in R (lme)

I'm trying to test for the effect of soil moisture on transpiration rates. I have plot-level data for 18 plots in 6 different stands of trees (3 plots x 6 stands). I want to treat "stand" as a random ...
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0answers
26 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 ...
2
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2answers
92 views

What is the right way to analyze a nested design in R?

I know that there are already a host of questions about nested designs but many of them haven't been answered or come from biological domains which I sometimes find hard to transfer to my domain. I ...
2
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0answers
106 views

Random Effects Tobit Model

I'm studying the effect of various criminal case and court district characteristics on sentence lengths. I was planning on running xttobit in Stata because I have individual defendants/cases within ...
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1answer
63 views

Nested ANOVA in SPSS / Science Education

I am analyzing student performance on a pre/post test designed to assess gains for a week long high school biology curriculum on natural selection. After comparing pre/post performance using a ...
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0answers
44 views

Unstable models, repeated crossvalidation, feature selection

I'm still trying to classify few (about 200) samples in a high dimensional feature space (dim=19) into 3 (very unbalanced) classes. I use an implementation of Least Squares SVM with one vs one coding ...
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0answers
42 views

Nested logit program in R

My question is specific to transportation modelling using a nested logit (NL) model. I wonder how to make a program including a t-parameter, t-value, and likelihood in R. I did estimation in a ...
3
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2answers
127 views

What to do AFTER nested cross-validation?

I've searched exhaustively on this forum and elsewhere, and have come across a lot of great material. However, I'm ultimately still confused. Here's a basic, concrete example of what I'd like to ...
1
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1answer
131 views

Random factor nested in two fixed factors

I have read Random effect nested under fixed effect model in R, but I have a doubt: My data is on germling survivorship, I have Temperature as a fixed factor (2 ...
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0answers
42 views

Including nested random effect in a GAM

We have 6 transects at 6 different sites (6 transects per site). Each site subdivided into two zones therefore in our model we have: Site (fixed categorical factor) and Zone (random categorical factor ...
0
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0answers
36 views

Can all the p-values from drop1 models be high even when the p-value for the full lm model is low

I have used the R lm() function to fit a model with one numeric and ten categorical variables. The p-value reported for the regression is very low: Residual standard error: 2.459 on 320 degrees of ...
2
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0answers
40 views

Data Mining Methods with Nested Data

I have three general questions that I am really struggling to answer: a) When we have nested data (e.g. employees nested in departments which are nested in companies which are in specific ...
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0answers
57 views

question about multi-level modelling with nested data (R/Stata/SPSS)

I have a dataset composed of observations taken from 16 separate experimental panels, each nested into one of 4 conditions (Treatment A Level 1, Treatment A Level 2, Treatment B Level 1, Treatment B ...
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2answers
614 views
0
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0answers
100 views

Mixed model, repeated measures, nested?, nominal data

I am not sure how to approach the statistical analysis of the following study. Any insights would be greatly appreciated. Thanks! So, I have two independent groups, group A and group B. I am ...
4
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0answers
114 views

Nested ANOVA: Unequal sample sizes? Variance components?

I am completely out of my depth on this, and all the reading I try to do just confuses me. I'm hoping you can explain things to me in a way that makes sense. (As always seems to be the case, "It ...
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0answers
41 views

Poisson Regression Nested Design

At the moment, I'm trying to do a 'Poisson Regression'. I have several years (2004 to 2012) with four seasons in each year. My dataset consists of the amount of carcasses found every 10 days, and the ...
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0answers
23 views

Nested Design, Split-plot or ANOVA

I have general statistical question concerning the analysis of two-factorial experiments. I would like to compare several response variables (biovolume, richness etc.) of two experiments (homogeneous ...
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0answers
77 views

Including a nested factor as random effect in a GLMM

Good afternoon, I'd like to ask for advice on including a nested factor as a random effect in a GLMM. I've read other threads in this forum, but still am not able to answer my question. Any help is ...
1
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1answer
48 views

Is a model nested within itself before collapsing categorical variables?

If I have a model with a categorical variable $X_1=\{0,1,2,3\}$ and a continuous variable $X_2$, and I have a regression model that includes an interaction between $X_1$ and $X_2$, then I decide I ...
0
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0answers
17 views

How do I test for equal variances in a nested design?

I've got a dataset where stations (3) are nested within beaches (5). Every station is replicated 6 times per beach, so that I have a total of 90 observations. I now want to test for equal variances, ...
4
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1answer
157 views

Linear regression - are my models nested or non-nested?

I’ve got two main groups, which I am comparing, a) rats and b) rabbits. Each group consists of two subgroups – breed 1 and breed 2. Using linear regression, I would need to find out, does a model ...
1
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0answers
117 views

Fixed, random effect and nested factor in lme

I have a dataset with the following variables: Treatment : (fixed,3 levels) Location : (fixed, 4 levels) Sample (random, 5 levels): 5 samples are taken in each location (randomly) Subsample ...
3
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0answers
20 views

How to analyze data with a lot of missing data (including covariate, nesting and blocking)

I have data set that was haphazardly collected to test grazing impact on soil. To test the grazing impact, 6 replicate soil samples were collected from inside a fence and 6 replicates were from ...
0
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1answer
15 views

SVMs for nested/prioritzed text document classes.

Let's say A, B, C, D, E, F are classes of text documents (i.e. sentences). Usually they occur distinctively, say: one document is precisely C. But sometimes one document is C AND A, at the same time. ...
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0answers
29 views

Need help with proper syntax for SPSS Mixed [closed]

I am having trouble building my model properly, and I was hoping I could get some advice here. I have a 2 (S: P vs. D) x 3 (ET: CA vs. CO vs. AD) between-subjects design. Participants were run in ...
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0answers
88 views

Very Low ICC in HLM

I ran a HLM analysis (One Way ANOVA with random effects model). I calculated my ICC and it is very small (00.1%). I understand this means that there is basically no meaningful level-2 variability in ...
0
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0answers
85 views

Mixed model regression with non-independent (nested?) data in r

I am having trouble modeling a regression with seemingly non-independent, nested observations. I am examining the effect of relatedness on proportion of offspring in cases of multiple males ...
0
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1answer
81 views

Nested design with pairing

I have been asked to help a colleague with analysing the following experimental design. 2 treatments (fixed), 5 time points (fixed) with 4 animals (random) at each time point. The animals within each ...
1
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0answers
25 views

How do you control FWER when testing multiple nested models with likelihood ratio tests?

Suppose I have three different models $M_1, M_2$ and $M_3$, these models are nested such that $M_1 \subseteq M_2 \subseteq M_3$. I perform two likelihood ratio tests, $M_1$ against $M_3$ and $M_2$ ...
0
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0answers
154 views

Dealing with nested factors and correlation structure in a GEE model

This question is of a previous one that has not been answered yet (see the details of our experiment and question here). We are now exploring a GEE (Generalized estimating equation) approach that ...
0
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0answers
36 views

How to analyse spatially and temporally dependent data?

I would be very grateful if anybody has some suggestion about how to deal with the statistics of the following experiment. I am planning to study soil characteristics under different trees in soil of ...
0
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0answers
21 views

Compare variance and point statistics in a 3 way group

I need some help on this analysis. I have 3 groups of individuals, different the level and kind of physical activity. For each individual I have the heart rate, taken every minute for ~24h. (each ...
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0answers
82 views

Nested Anova Question:

I've a dataset for measurement of protein marker abundance for two groups of individuals, Treatment and Control. Within these two groups there are several subjects and for each subject there are three ...
4
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1answer
149 views

GLMM model specification help gender effects + an effect that is nested only within female

Main question: "What are the contributing variates to daily movement distances?" Specifically my question today relates to: "What is the contribution related to gender, and then within female what ...
0
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0answers
66 views

What to use: Nested Case-Control or Case-Cohort?

I am following a cohort of patients over time from which I am planning to sub-sample a sub-group of patients to pilot a new intervention. The plan is to compare the effectiveness of the new ...
0
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0answers
64 views

Why variances from nested random effects appear identical?

Could anyone shed some light on a slightly confusing result from a lmer4 model in R? I have a nested random effect, but the variance explained by each level seems identical, and I can't see why. I ...
3
votes
1answer
143 views

The test statistic in the likelihood ratio test for nested linear models

Imagine that we have a family of probability disributions with p.d.f $f_{\theta}(z)$ where $\theta \in \Theta$. We also know that there is a linear dependence between parameters. As a consequence we ...
6
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1answer
315 views

Why can't likelihood ratio tests be used for non-nested models?

More specifically, why do the likelihood ratio tests have asymptotically a $\chi^2$ distribution if the models are nested, but this is no longer the case for the not-nested models? I understand that ...
2
votes
1answer
317 views

Using AIC to select between models that use nested and non-nested variables

I'm using SPSS to try and find a mixed model that adequate explains the data that I have. Two of the explanatory variables are closely related ('Sample group' and 'individual'), as an individual is ...
0
votes
1answer
165 views

From dummy coding to ordinal variable

I have read from multiple sources (like this pdf) that in a linear regression model, an ordinal variable can be obtained by imposing linear restrictions on its dummy coding. e.g. $x$ is an ordinal ...
0
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0answers
128 views

GLM with quasipoisson nested distribution

I want to make a GLM with a quasipoisson response distribution. My response variable is inflorescences by plant and my explanatory variable is coverage. For inflorescence counts, I used the average ...