Questions tagged [beta-regression]
Beta regression is useful when the dependent variable is bounded, or when it has a ceiling or floor effect. It can also be used for modeling both the mean and the variance.
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Interpretation of betareg coefficients where observations transformed to account for y=0 or y=1
I am running a beta-regression using betareg in R (with default logit link function). My response variable is a proportion, and may include 0 and/or 1. I've transformed the data following the betareg ...
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Why does MCMC estimate the variance in a logit-normal model incorrectly?
I am trying to estimate the variance $\varepsilon^2_X$ in a simple logit-normal model of the form
$ \sigma^{-1}(U) \sim \mathcal{N}(\mu_U, \varepsilon^2_U)$
$ \sigma^{-1}(X) \sim \mathcal{N}(\sigma^{-...
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Beta regression coefficient interpretation
I'm trying to use beta regression on a data set where the response variable is in percentage (i.e. between 0 and 1), so let's say it's the unemployment rate. I'm having trouble wrapping my head around ...
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Can you run a mediation analysis using beta regression
When running a beta regression in R I am interested in seeing if there are any potential mediators to my primary outcome. My primary outcome is bounded between 0 and 1 and I therefore am unsure I can ...
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Beta regression - simultaneously tracking all components so that proportions sum to 1.0
I am trying to fit a beta regression model in R with the outcome variable representing proportions, so that the model accounts for all of the constituents of the whole fraction. I am unclear how to ...
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How to relate prevalence to factors with multivariate analyses model (GAM beta inflated)?
While analizing the prevalence of cows to brucellosis (illness), and in order to relate it to a set of factors like country, state, and detection technique, I need to apply a multivariate analysis ...
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Beta regression: slope of scaled predictor
I want to fit a beta regression with an scaled continuous predictor, and express the slope in terms of proportion (not at the transformed, log-odds scale). In other words, I would like to express the ...
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Dominance analysis with a random-effects beta regression: nested random effects throw error
The goal
I want to run dominance analysis on a mixed-effects beta model, to approximate the relative importance of a set of predictors (2 factors, 1 scaled continuous, 1 continuous with splines). The ...
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Bounded variable: beta regression or switch to ratio?
My task is to study factors that influence the composition of labor force. The latter consists of two types of workers, full-time and part-time. My first approach was to run an OLS regression for the ...
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In Beta Regression we obtain predictions of the mean response, do we therefore assume that the response is B(mu, var) around those predictions?
The title question here is a bit awkward because I'm really asking if this illustration I've drawn is true:
Suppose we have a Beta Regression of one predictor, X, which is used to model both the ...
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How to model proportion data from an online experiment?
I have designed and run an online experiment in which we've slightly changed parts of a web page. Let's say users visit our website to place food orders and the order funnel looks like this: home --&...
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Estimating Exponential Decay Rate and its confidence interval from Beta Regression Odds Ratio fit
I am working with a random variable that is bounded between 0 and 1, and its mean decreases exponentially over time. I am seeking to estimate this exponential decay rate with its corresponding ...
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Overdispersion in a beta regression? (DHARMa package)
I'm trying to run a beta regression to predict my dependent variable Consistency, which has values between 0 and 1.
Here is the distribution of Consistency values in my dataset:
I originally tried ...
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gam() in R package mgcv for Beta Ridge Regression
I have many questions regarding this package. According to my understanding s() in gam() perform as shrinkage parameter of Ridge ...
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emmeans for betareg is giving me identical arrow ranges when plotting comparisions = T
My response is a ratio (length of a discoloration disease in the plant divided by the height of the plant), so is always (0, 1). Actually, sometimes it could be [0, 1), i.e., including zeros.
As I ...
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Interpreting coefficients of beta regression
I have implemented a beta regression and am a little confused on how I should interpret the coefficients of my model. For context, both my independent variables and dependent variable are expressed in ...
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Interpreting coefficients of beta regression
I have implemented a beta regression and am a little confused on how I should interpret the coefficients of my model. For context, both my independent variables and dependent variable are expressed in ...
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Explanatory model for zero-one inflated bimodal data with random effect and binary indepentent variable
I'm trying to evaluate the influence of a single binary explanatory variable on a 0-1 scale response, with one grouping factor. The response variable is generally 0-1 inflated. The simplest solution ...
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Converting dispersion to standard deviation in a beta regression
I'm unsure about the relationship between dispersion estimates (precision^-1) from beta regression models (log link) and the standard deviation.
The left panel is from a glmmTMB model ...
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how to interpret estimates from Beta GLMM with dummy explanatory variables
I have results of an experiment where each person had to estimate a share of certain types of city dwellers in two cities (A and V), and participants were assigned into one of two treatments (FIN or ...
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How to write a generalized additive model, fitted in R programming language, in a mathematical form? [duplicate]
I have fitted a model in R programming language. My dependent variable is disease severity and my predictors are weather variables. How can I write this model in mathematical form for a manuscript? Is ...
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How to account for different trial durations in mixed models?
My experiment was conducted in multiple years. Each year, plants were sown in an infested field and then harvested after a certain time. There was a weather station to record weather data. I would ...
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Zero Inflated Beta Regression (ZOIB)
I'm using R to model zero inflated beta regression. Upon reading some documentation for the ZOIB package, I came across some functionality for adding random effects to one or many of the link ...
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Calculating Mediation Indirect Effects using GSEM in Stata or R for Count (Discrete) Mediators
Estimating the following model in Stata helped me get the direct effects. This is a set of three models, a beta regression with the final outcome as the dependent variable, and two mediating negative ...
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Truncated Poisson vs ordered multionomial + beta regression
I want to model a random variable that takes values between 0 and 1, and where 0 and 1 are included. Zero and one are possible values of the random variable and occur frequently. I have several ...
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Model specification for skewed proportion as dependent variable
I am struggling with assessing the best weighted regression type/model specification for my problem.
The goal is to determine influence of independent variables towards the outcome (dependent variable)...
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Why beta regression?
According to http://r-statistics.co/Beta-Regression-With-R.html, the topline remark is:
Beta regression is used when you want to model Y that are probabilities themselves
Grammar aside, one may ...
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Getting a warning in beta regression model "Warning: no valid starting value for precision parameter found, using 1 instead"
I'm getting a warning message (Warning: no valid starting value for precision parameter found, using 1 instead) while fitting a beta regression model using ...
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How to account for multicollinearity between weather variables in generalized additive models?
I investigated the effect of weather variables on disease severity. My response variable is proportion of disease severity observed in different years. The study is conducted over 10 year and disease ...
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Is there a way to convert beta regression coefficient in odds ratios?
I'm currently working on a meta analysis and half of the included papers only reported the beta coefficient. I wanna pool the odds ratios and am now wondering if there is a way to convert beta ...
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Can the Beta-regression be written in the GLM form?
The Beta distribution is:
$$p(y)=\frac{\Gamma(\alpha+\beta)}{\Gamma(\alpha)\Gamma(\beta)}y^{\alpha-1}(1-y)^{\beta-1}
$$
It's part of the exponential family.
We can reparametrize this with using mean ...
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GLM or beta regression, with proportion data, and many 0 and 1
I am trying to see if some anthropic variables (e.g., PopdensityAvg) explain animals' distribution. My dependent variable is the area occupied (...
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Comparing models with the betareg packpage
I'm having problems using betareg. I have a dataset that always shows different results depending on how I perform the analysis. I'm using ...
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Best regression model for ratios of a zero-inflated Poisson with a zero-truncated Poisson random variables?
I am working with data in which my dependent variables underlying probability distribution is a ratio of correlated ZTP-ish (ZTP = Zero-Truncated Poisson) random variables $Y = \frac{M}{C}$ with $C \...
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How to improve model's predictive accuracy brms / rstan
General question: How can you improve a model after seeing that it poorly predicts your data (i.e. posterior predictive distribution doesn't recover your data well)?
I am fitting a multilevel beta ...
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Modeling the precision and location parameters in beta regression
Is there any technical or substantive reason to typically want to ensure the location $\mu$ and precision $\phi$ parameters in the beta regression model include the same fixed or varying predictors?
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Beta regression (proportions) with phylogenetic comparative analysis?
Is there a package in R that allows phylogenetic comparative analysis of proportion data (i.e. a beta distribution)?
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Logit GLM and logit beta regression: Practical difference in the interpretation of the coefficients?
Terminology: By logit GLM I mean a generalized linear model with a binomial distribution and a logit link function. By beta regression I mean beta regression with a logit link function.
I understand – ...
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Proportion data with number of trials known (and separation?): GLM or beta regression?
I perform a lot of bioassays in which I score mortality not on individuals, but on groups of individuals as a proportion (the denominator, i.e., number of trials, is known):
Sample Data:
...
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Beta regression shows a weird plot
I am trying to model the relationship between my response 'crop coverage [%]' ~ weed coverage [%] + Soil Moisture [%] using R. Since I am dealing with proportions, I chose to do a beta regression. ...
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Beta regression using categorical variables
I have been asked to do beta-regression for my data. The independent variable is categorical (there are three treatments A, B and C). The dependent variable is the proportion of time an animal is ...
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How do I write out the components of my beta regression, and how do I interpret them afterwards?
I am estimating a beta-regression using the logit-link function with a continuous dependent variable bound between 0 and 1 and 5 continuous predictor variables.
In R the equation is given by: betareg(...
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Why are predictions from beta regression and linear regression identical?
I'm utilizing a beta regression to predict the relationship between x and y, since y is a proportion variable confined within the interval [0,1] but has no values of either 0 or 1.
Outcomes on y only ...
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Why does my beta regression look linear when plotted?
Im using a beta regression to model since my dependent variable is confined between [0,1]. However, when I plot the relationship between x and y via my beta regression, the effect looks linear. When ...
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Fitting a beta mixed model
I would like some clarification on fitting a beta mixed model.
My dependent variable is the proportion of days that patients take medication. For every patient(Patient.ID), the pharmacy either had an ...
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Appropriate Regression Model for Proportions and Rate Data
I have a problem where my dependent variable is given as a click-through rate and thus bounded [0,1]. While I have the traffic for each sample (a combination of design factors) and could reconstruct a ...
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Calculating different pseudo-$R^2$ for a betareg model
Sorry if this is a bit long..
I've been trying to fit models predicting the % of area infested in a field (response between 0 and 100%, total of 61 fields), with four explanatory variables, two ...
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How can I calculate a beta regression prediction from the coefficients?
I have applied the R betareg function to my data using the default logit link and phi precision log-link for the categorical data. My equation is:
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GAMM with BETAR(Link = "Logit") [closed]
I'm trying to use betar in gamm4 models but keep hitting an error. As far as I can tell, betar is one of the families that should be available - can anyone identify why I would keep hitting this error?...
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Beta regression for ratio of counts
I have a question about whether it is appropriate to use beta regression when the proportion is formed as a ratio of counts. I have seen information suggesting it is fine and others pointing out that ...
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