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Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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Comparison of paired count data between two treatment periods with different length of follow-up

I am currently using SAS 9.4 to carry out a retrospective analysis of patients who switched from drug A to drug B. I am interested in assessing the hospitalization counts before and after switch to ...
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Is a single count data point significantly different from a set of reference count data

I have counted the number of occurrences of protein domains in the proteomes of 16 different insect species, 1 focal vs 15 reference species. For each of the ~4700 protein domains in my data, I have a ...
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How can I compare how significant is the difference between three or more distributions of count data?

I am researching whether software developers use different numbers of communication channels when performing different activities. Therefore, I would like to know whether, depending on the activity, ...
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Is my data inappropriate for a zero-inflated regression model?

I am working with count data where I have an abundance of zeros for one of my categorical factors (Day). I have generated two models, p1 and m1, with zeroinfl() and ...
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Differences between sample proportion within conditions and between conditions

please let me share with you some problems and ideas: I am conducting a research in which I have 6 types of answers (e.g. A, B, C, D, E, F) in 32 questions And two conditions (e.g. M, N). (each ...
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Modelling count data with time-series structure and predictors

I am doing an analysis of sales-data over a period of time (i.e. over a few years). Those sales-data are also dependent on some predictive variables (i.e. holiday, weekend, weather,...). The daily ...
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Modeling and testing for trends in hospital-surveillance (count, event) data

Intro Hi all, I'm working with hospital-based surveillance data. My peers and I are trained (loosely speaking) as frequentists. I'm mindful of the aphorism: Statistics: A subject which most ...
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Zero-inflated vs not Zero-inflated models for count data

I am analyzing a small dataset (d) of urinary track infections in a group of residents of a long-term care institution over a period of 6 months. The total number of patients was 29. I had used ...
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What model should I use? Time series count data grouped into provinces. R

I have daily observations on the count of a variable, with 1,000 daily observations across 15 different provinces, for a total of 15,000 observations. On certain days, there is an exposure, which may ...
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Are fitted.values available in pglm?

I am using the pglm function in R to fit a Poisson fixed-effects model. According to the documentation, the pglm object should have fitted.values. However, fitted.values(model-name) returns "NULL". ...
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Finding GLMMs that fit my count data for multiple datasets

I need some help finding a model that fits my data. I'm using GLMM's to test the effect of nitrogen level (numerical), species (two-level factor), and the interaction between these two variables, on ...
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R GLMM: How to deal with separation inflating standard errors in negative binomial regression (count data)

I'm comparing counts of individuals between different localities, and between two seasons (seas_wmo with levels dry and ...
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2answers
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Poisson model appears overdispersed, but usual recommended approaches don't improve fit

Summary: I am trying to model some count data. I initially attempted to fit a poisson GLM, but diagnostics appear to indicate overdispersion. I have tried several different recommended remedies but ...
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Are median values numeric or ordinal?

I'm trying to set up the input data that I'd feed into my DL model and for the simplicity, I'm thinking of plugging in only the min/max/average values of the original data. (This is necessary for my ...
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GLMMs for count data with glmmTMB: random slopes specification, cross-level-interaction and strange results

folks, I recently found the great glmmTMB package which I hoped would help me with my models. My data are 60,000 facebook posts that are nested in 51 companies (i.e., the posts by these companies). ...
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Testing for non-zero values above and below the diagonal of a matrix

I have a $n\times n$ contingency matrix comparing count data (classification) of two procedures. I want to test for non-zero values above and below the diagonal (different classifications in both ...
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Why does pglm give different results thans log-plm?

I'm looking to regress a fixed-effects model on count data. My initial approach was to take the log of regressor on R's plm package. Then I found out about the pglm package, which enables general ...
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Asymmetric data analyses

I have a data set containing bacterial count values before treatment and after treatment. These data look asymmetric. Please advise me for a suitable statistical test to find if the introduction of ...
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1answer
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Linear regression where some known records have a measurement error in dependent variable

I am modelling data where the dependent variable is the number of units of a certain product sold each month in each area. In all areas, the product is sold by a chain of shops 'A' and we have exact ...
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Which kind of diagnostic plots for count data? [duplicate]

I know that for an lm model is enough to run plot(model_lm) to get diagnostic plots. I am dealing with high-dimensional count ...
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Wald test for Poisson distributions

This question asks: $N_A$ and $N_B$ are variables of the counts of the number of events 'A' and events 'B' respectively. Those variables follow Poisson distributions with parameters $\lambda_A$...
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How do I model count data (Poisson regression) that has a seasonal pattern?

I'm rather new to R and poisson regression and have a few questions. I have count data of incidents per month, a couple years prior to an intervention and 1 year after. I want to use poisson ...
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Predict a disease with a compositionnal count data

I am trying to predict a disease (binomial response TRUE or FALSE) with count data (16S microbiom count) and I got one random effect (person's mother). Actually, im working on count's proportion ...
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1answer
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Using `glm()` in R for correlated count data (data provided)

I have data from one group ($n = 25$) of subjects pre- and post- tested on an $15$-item dichotomously scored test (see below). Given that the data are from the same subjects (i.e., correlated), how ...
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Can Count data be used as predictors in a linear model [duplicate]

If someone is trying to predict a continuous measure (satisfaction) and their 2 predictors are discrete count data, can that person use a basic linear model (like lm...
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Accounting Student taking Master in Stat, need your help regarding taking subjects

I had a Bachelor in Accounting and now I'm doing a Masters in Statistics. This is my first semester and I have to Choose at least 3 out of 6 offered subjects for this semester. These subjects Are: ...
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Incomplete block design analysis

I have 4 treatments (6m, 12m, 24m, 40m) in 3 blocks, but all treatments are not replicated in these blocks: 6m, 12m, 24m are in Blk1 and Blk2 and Blk3 consist of only 34m (control plot) and 6m. How ...
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1answer
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Which regression used for normalized count data

I am working with social network data. I have multiple networks of various sizes and I'm calculating indegree (the number of connections between people) in each of the networks. I've been told to ...
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1answer
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Mixed-effects Generalised Linear Model (GLMM) to detect significant differences in bird observation data

I am trying to analyse a set of bird count data associated with an environmental impact assessment I am running, but require experts to get this right. I am unsure how to formulate the model and ...
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Should ANOVA be used when the dependent variable is an integer, such as a count of items? [duplicate]

I have data for a dependent variable, DV, representing a count of objects, with a range from 0 to 6 (sample size 450), slightly left skewed with a mode at 4: Furthermore, I have a single categorical ...
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How to make sense of dependent count data in a generalized linear model?

I am investigating whether fitting my data to a generalised linear model is a) possible and b) worth it. My data set is a list of retrospective-longitudinal patient medical records. I am able to ...
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Methods to find relationships between counts

I am looking for if there is any statistical method(s) to view if there exists any relationship between counts. I have a large astronomical type of dataset but for the sake of breaking it down for an ...
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1answer
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Why doesn't the zero model in a hurdle model exactly match logit result?

I am relatively new to R and I suspect that there is user error here, but I cannot figure out why the output from the logit in the hurdle model does not match the prediction of the "zero" function in ...
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1answer
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Is there a statistical test for comparing count/frequency of different groups (just one dimension)?

This seems very simple question, but I could not get my head through it. The data is like below: In the sample of 30 patients, patients can have four types of treatment. we want to know whether B ...
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1answer
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Chi-square test with replicate nested

I have a question about how to analyse count data with replicates nested in each treatment. For example, imagine temperature can influence the sex ratio of mosquito larva emerged from eggs. I have two ...
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1answer
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How to establish the effects of a competitor near my store location?

As part of my studies of statistics, market analysis and data analysis, I’m facing the following problem but not sure if the answer I’m proposing it is correct or not. A commercial retail store with “...
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Comparing species correlations between species in two habitats

I have two community data sets (samples as rows, species as columns, populated with abundance). This data comes from two habitats/sites, with differing numbers of samples at each site. What I want ...
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1answer
114 views

Variable Selection for Negative Binomial Regression

First off I apologize, that I cannot share the code or details about the variables for this project. I am new to statistics and am working on a project using count data. I want to make sure I am going ...
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1answer
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Compare species count data between sites

I'm comparing species counts between areas. My data is very similar to the below. ...
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1answer
59 views

Calculating 95% confidence intervals for GLMM additive coefficient - count data estimates

I am running a GLMM on some data where the response is count data, using the glmmADMD package in R. I would like to plot the results giving estimates for the response variable with certain explanatory ...
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1answer
84 views

GLM for count data with all zeroes in one category

I have a GLM where the response variable is count data and the predictive variable is a factor with 4 levels. I used a negative binomial distribution to model the relationship between both variables (...
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Goodness of fit for zero truncated negative binomial model

I have calculated a zero-truncated negative-binomial model using glmmadmb, and also vglm, in R. I need to report some measure of goodness of fit for this model. I have already done cross validation (...
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1answer
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How to standardize count data for different sampling site sizes

I want to do a linear regression for my data but I’m not sure what I need to do with my raw data before running a linear regression. I have counts for species in several forests of differing sizes. I ...
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2answers
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GLMM species count data with transects

I am trying to create a GLMM model which explains differences in abundance/count of three species of scorpion around a field reserve in different forest types. -I have 7 trails in different forest ...
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Checking equality of coefficients from two different count data regression models

Suppose, I have cluster survey data. Individuals are nested within cluster. My outcome variable of interests are two count variables Y1 and Y2. I have a set of predictor variables X1, X2, ... X5. Now ...
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Negative Binomial having count data with an upper bound

The general statement is that you cannot use Negative Binomial or Poisson with count data with an upper bound, which makes sense. However, in my case my count data is always much lower than the upper ...
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Why there are not (long tail) alternatives to dirichlet-multinomial (while there are for posisson-gamma)

While there are a lot of long tail alternatives to poisson-gamma (negative binomial), for example (Source) I haven't found any work on replacing the dirichlet distribution with a more long tailed ...
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Predicting Negative Binomial response when some observations contain no success

Problem description: I am attempting to model the number of attempts required in order to make event $Z$ happen. Each day we make $k_i$ attempts with setting $X_i$ (a vector) in an effort to make $Z$ ...
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Population Mean Estimation using Poisson Regression?

Assuming I have count data, where x is the counted variable of interest and y is some total number of counts for a given sample. Then, can I improve my estimate of $\mu_x$ by using a Poisson ...