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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
9 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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23 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 ...
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1answer
18 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 ...
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10 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, ...
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1answer
97 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 ...
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0answers
32 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 ...
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0answers
18 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 ...
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1answer
13 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
17 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
22 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 ...
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0answers
35 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 ...
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1answer
45 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 ...
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0answers
19 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 $M_2$ ...
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0answers
55 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 ...
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0answers
31 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 ...
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0answers
16 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
63 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 ...
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1answer
125 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 ...
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0answers
34 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 ...
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0answers
47 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
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1answer
125 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 ...
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65 views

nested design after anova tukey

so I analyzed a nested design (split-plo, 2x4 factorial) with ANOVA and it indicated that there are differences in the levels of factor b. I went on with t-tests comparing the means depending on ...
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1answer
212 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 ...
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1answer
217 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
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1answer
114 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 ...
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0answers
79 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 ...
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1answer
626 views

Structuring a linear mixed model in R with nesting

My ecological question is: "What are the trends in percent coral cover by island and depth across the state of Hawaii from 1999 to 2012?" I am trying to analyze this hierarchical data set using R ...
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50 views

Is this a nested model?

I have a dataset with explanatory variable $X$ and response variable $Y$. Besides, there is a two-level factor $S_{j}, j=1,2$. The random error variance might be different between these two strata. I ...
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0answers
21 views

Random factor nested within fixed factor under Bayesian approach

I am working on my posgraduate thesis using horse competition data to estimate genetic parameters of performance, basically time and placing traits. By means of a Bayesian approach I would like to ...
2
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1answer
125 views

Is this a nested model and can I use the likelihood ratio test?

I have a data set, total_data and I applied a model to it. For instance, the model has one parameter $\beta$, and I calculated the log-likelihood of the fitted model (using maximum likelihood method). ...
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0answers
281 views

Nested Logit model in r

I am trying to run a nested logit using mlogit in R to analyze data from choices people made. There are 4 possible alternatives they could choose from, but in any given choice situation a person had ...
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0answers
94 views

Nested test to remedy pseudoreplication

Data structure: I have two datasets from two protected areas that differ in protection status. Both areas contain 43 and 37 sites each. Question: I would like to know which test would be the best ...
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1answer
416 views

How do I set up a multivariate hierarchical multiple linear regression in R?

I have two continuous DVs (measurements taken on individual fish), one continuous individual level IV (fish's size), and two site-level IVs (PC1 and PC4). Sites are either take or no take. There are ...
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1answer
72 views

Nested Models for Likelihood Test

If I have a logistic regression model with 3 predictors, $x_1$, $x_2$, $x_3$, and then I remove $x_3$ from my model (left with only $x_1$ and $x_2$), are those models nested? And therefore I can use ...
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2answers
261 views

One-way repeated measures anova

I tried finding an answer to this question on this and other sites but to no avail - if I am missing something please excuse my inability to locate the answer! Basically I have several dependent ...
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0answers
222 views

Mixed model repeated measures, nested

I have a study in which I have 3 groups of crews (4 crews in each group) in which there are two people (L/R). Each crew experienced 4 lighting treatments (D1-4), once in one position, and again in ...
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0answers
92 views

Nesting and grouping formula confusions using lme

I've seen a fair few of these posts already, and I feel a bit silly for posting yet another question on the topic - but I just cant seem to get my head around it. I'm very new to R and esp new to lme, ...
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0answers
106 views

Nested vs random effect

I'm having a little trouble analysing a data set from the following experiment: we applied 4 treatments (control, ...
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2answers
141 views

Nesting / hierarchical modeling in a pre-post study

We are conducting a study which has a pre-post design. The unit of the study is the outpatient visit. In each visit, we study how patients and physicians interact. Each physician will see between ...
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1answer
336 views

When to include a random effect in a model

I'm new to mixed modelling and i'm confused as to whether its appropriate to use a random effect in an analysis I'm doing. Any advice would be appreciated. my study is testing how well a newly ...
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0answers
121 views

Nested mixed model

I have a data set where we have collected fish for behavioural experiments from different areas and within each area we have selected a clear water site and a eutrophied site. We then brought the fish ...
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0answers
140 views

Nested repeated measures analysis

I have a nested repeated measures question. I have 20 individuals grouped into 5 families. For each individual I have measurements on subsequent days pre, during, and post-treatment for a total of 6 ...
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0answers
202 views

When to use likelihood ratio test vs. incremental F-test in nested nonlinear model selection?

I have two nested nonlinear models and I want to know which provides a better fit to some data. I see descriptions of both the likelihood ratio test and of the incremental F-test (also called the ...
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1answer
456 views

Biased estimates when intercept is included in a linear regression

I am simulating 10000 data-sets, each of length 20, that follow an autoregressive model with lag 1, using the following code: ...
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1answer
1k views

Nested/SplitModel - RepeatedMeasures/MixedModel ANOVA: levels of nesting & scripting in R

My data set has the following variables: Treatment (4 types- fixed) Location (8 locations- fixed) Position in Location (3 positions per location- fixed) Samples are taken in each position (3 ...
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1answer
208 views

Can higher level be insignificant but lower level significant in a nested ANOVA?

I have ran a nested ANOVA on a data set and the results suggest that there is an association for the higher level with an insignificant P-value but also an association for the lower level with a ...
4
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0answers
88 views

Can I validly expand the odds ratio analogously to the relationship between relative risk & the incidence rate ratio?

I am involved in a nested Case-Control study that involves cohorts of cases and controls entering a program, with the outcome of failure by six months. Cases and controls are individually matched on ...
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1answer
180 views

Nested or Split plot

I have a design with four factors Frame (positive negative neutral) Graphic ( graph no graph) Color (red grey) nested in graphic Position of color (nested in color, which is nested in graphic) ...
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1answer
270 views

AIC for non-nested models: normalizing constant

The AIC is defined as $AIC=-2 \log(L(\hat\theta))+2p$, where $\hat\theta$ is the maximum likelihood estimator and $p$ is the dimension of the parameter space. For the estimation of $\theta$, one ...