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Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

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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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0answers
14 views

Can Count data be used as predictors in a linear model

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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1answer
35 views

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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1answer
10 views

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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14 views

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
35 views

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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0answers
34 views

Should ANOVA be used when the dependent variable is an integer, such as a count of items?

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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0answers
41 views

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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1answer
39 views

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
45 views

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
29 views

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
27 views

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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38 views

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
54 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 ...
2
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1answer
62 views

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
35 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
54 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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0answers
16 views

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
37 views

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
64 views

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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0answers
7 views

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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0answers
55 views

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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0answers
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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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2answers
40 views

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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1answer
33 views

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 ...
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2answers
91 views

Mixed Effect Model - Roadkill hotspot v. coldspot

This problem concerns road mortality. We have 4 highway sections of varied length that were flagged as problem areas for road mortality with large mammals (moose, deer, elk, and even cows). We used ...
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0answers
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can i use random forest for feature selection and then use poisson regression for model fitting? [duplicate]

Variables that are important in random forest don't necessarily have any sort of relationship with the outcome. So would it be wise to use random forest to gather the most important features and then ...
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0answers
15 views

Use or not use a count variable when data is static

I have a dataset of objects (e.g. toys) for which we keep over the years a count of specific events (e.g. minor incidents). Based on this count, I'm trying to predict for each toy if an accident is ...
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2answers
199 views

GLMM for count data using square root link in lme4

I have data from a field survey. The objective of the study is to relate number of seedling (respond variable, count data), landform (exploratory variable, categorical variable with 3 levels) and ...
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1answer
41 views

Compute a measure of explained variance for hurdle models in R

I am working with a dataset df which comprises count data count and a number of categorical variables. ...
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0answers
36 views

How to Normalize Counts Correctly?

I am not sure what is this type of problem called, so a ref would do wonders. I am calculating the heritability of diseases among a population. Here is the catch: the age distribution of diagnosis ...
2
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1answer
24 views

How do I specify an outcome variable (y) as count data using a poisson regression in a multilevel model?

I have three variables with multilevel data: Level 1 DV: deviant behaviour Level 1 IV: negative affect Level 2 IV: consideration of others (personality trait) Here is my model: ...
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1answer
31 views

Which test should I use to determine a relationship between Social media activity and calls booked from activity?

We run a business and I am trying to calculate the worth of spending time on our social media groups to book calls with potential clients. I have a list of social media activity for the last 60 days (...
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0answers
15 views

Plant density and spatial relationships

I have an experiment that investigates the affects of small mammal presence (present or absent) and fire (burned or unburned) in a replicated full factorial block design (4 plots--each treatment combo ...
2
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1answer
51 views

Non negative time series

I've been given to analyse a continuous non negative time series. Please give me an idea of whether I can use normal time series analysis for this or should I use differently. Also when converting a ...
2
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0answers
40 views

Prediction interval for sampled count data

I am trying to get prediction intervals around a sampled count variable. For example, say I want to know the number of letters an apartment building receives every day. Each day I record the count ...
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1answer
25 views

Should I use Structural Equation Models (SEM) for my Functional Diversity (FD) study? (ECOLOGY RELATED)

I'm trying to calculate various functional diversity measures (Fric, Feve and Fdiv) for bird communities by using count data which is collected annually. My ultimate aim is to compare functional ...
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0answers
38 views

What are models for count data where the variance is not related to the sample size?

For modeling count data that arises as the sum of Bernoulli random variables or according to an occurrence process with constant rate in some interval, there are many techniques, like using a Binomial ...
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1answer
302 views

Zero-inflated count data simulation in R

I need to simulate data to explore the question: "What happens if my data have zero inflation, but I ignore it and fit a standard count model instead?" More specifically, how can I add zeros in a way ...
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0answers
32 views

Is Expectation-Maximization the right type of analysis (& if so, how)?

I have 118 microbes that I have tested at various concentrations of a drug that is supposed to kill them (0.1875 - 15). However, these microbes have mutations (A-H) which confer resistance to the ...
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1answer
42 views

Why is it unacceptable to use binary or count dependent variables in OLS?

I know this is a basic question but I really want to make sure I fully understand the reason's why this is the case. If possible, can someone help explain to me as simply as possible why it is bad to ...
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1answer
25 views

Statistical test for count data passing a given threshold

Apologies if this question is painfully basic. I have a df of count data in which each row represents a box of marbles, some of which are black, and some are white: ...
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1answer
80 views

re-analysis of someone else's data: 5 treatments x 4 non-exclusive outcomes

I am trying to re-analyze (ETA: used loosely; the original study performed no statistical analysis) some published biological data (below). They used 5 treatments and scored presence/absence of 4 non-...
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1answer
169 views

What model to use with repeated measures of count data with a factor and a covariate?

My design involves three dependent variables. They are count data: frequencies of certain words used in a 20-min conversation. They're also repeated measure: the same subjects engaged in three 20-min ...
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0answers
16 views

How to model if a company is mentioned in a review (volume) and how it is mentioned (valence)?

I am working with social media data of Brand A and would like to model what features of posts of Brand A are linked to if a competitor (Brand B) is mentioned in the comments of different posts of ...
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1answer
54 views

zero inflated poisson iregression AIC values

Im trying to regress count data (DV). There are a few IV's both continuous and categorical. Frequency count of my DV as show below.Two groups , treatment and control. About 75 % are zeros. ...
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0answers
17 views

Normalizing counts with uneven annual populations

I have a collection of .25M digitized books published between the years 1700 and 1800, and am researching whether certain events that occurred in that period influenced annual plagiarism rates. The ...
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1answer
24 views

Manga translation updates: what kind of data/what model?

Long story short, I'm trying to predict how likely it is for a content creator to release new content or when they are most likely to do so (and possibly how this changes over time). My problem is ...
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1answer
89 views

How Can Poisson Regression Predict a Count of Zero? [duplicate]

I am reading "Modelling Count Data" by Hilbe and I feel I am missing something fundamental about Poisson Regression. $\hat{\mu} = \exp(\alpha + \sum\beta_ix_i)$ One of the requirements for using it ...
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0answers
286 views

XGBoost Poisson Objective Function When Data is Over-dispersed [closed]

I am modeling very over-dispersed count data with the goal of prediction. The data is not zero inflated (there are no zeros), but there are a lot of values of 1. ...