Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

1
vote
1answer
27 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 ...
0
votes
2answers
40 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 ...
0
votes
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 ...
1
vote
0answers
43 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 ...
1
vote
0answers
17 views

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 ...
0
votes
2answers
38 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 $Z$ ...
0
votes
1answer
30 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 ...
4
votes
2answers
74 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 ...
0
votes
0answers
12 views

Significant difference of small count data in 2xn contingency tables

My data consists of multiple contingency tables (2xN, often N > 30) with frequencies of two nominal variables: they are frequencies of shared collocations of various word-pairs taken from the corpus. ...
0
votes
0answers
8 views

Appropriate statistical test for frequencies of motifs

I have a graph composed of 26 nodes, labelled A to Z. Some nodes are connected by edges, but not all nodes are connected to all other nodes. I enumerate all possible sub-graphs comprised of four ...
0
votes
0answers
14 views

Can a worm plot be used with a count output variable?

I have a Gamlss model with a Sichel output variable and i am not sure if it is ok to use worm plot for validation. currently the worm plot looks like this:
0
votes
0answers
24 views

Normalize Count Data (Poisson Distributed Data) with many Zero Values

I have a count data set for the number of couns of an alert(over speeding alert) for various vehicles(number_rows=206). Please assume this count data is for vehicles who have covered similar amount ...
1
vote
0answers
30 views

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 ...
0
votes
0answers
14 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 ...
5
votes
2answers
182 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 ...
1
vote
0answers
30 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. ...
1
vote
0answers
30 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
votes
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: ...
1
vote
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 (...
0
votes
0answers
20 views

Does it matter whether left- or right- bin edges are inclusive when computing a histogram?

Supppose we have some data that we can compute a histogram for. The goal is to use the histogram to compute Pearson's Chi-Squared Test. When computing the initial histogram, we must decide whether ...
0
votes
0answers
20 views

Could continuous concentration data (ppb) ever be modeled with negative binomial?

We have data on compound concentrations (unit: ppb, continuous variable). There are many 0s. In fact, ~70% of the observations are equal to 0 (either true 0s or below the limit of quantification). ...
1
vote
0answers
14 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 ...
0
votes
0answers
29 views

Choice of statistical test

So, I have a study where I have collected gender, age and brand use (either user or non user). I am trying to determine what statistical test to use to determine if a particular brand has greater or ...
0
votes
0answers
11 views

optimal dissimilarity measure for time series count data

I have time series of three variables x,y,z. All are based on count data. Is there an optimal dissimilarity metric to obtain differences between respective pairs of x,y,z? Is it appropiate to use ...
2
votes
1answer
43 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
votes
0answers
31 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 ...
3
votes
0answers
35 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 ...
4
votes
1answer
130 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 ...
2
votes
0answers
29 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 ...
0
votes
1answer
35 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 ...
0
votes
1answer
22 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: ...
0
votes
0answers
13 views

Properly representing count data, multiple websites with vastly different traffic counts

Good day everyone, I am currently faced with the problem of trying to represent my current set of data correctly. We have a number of websites and each website has a number of hits spread across ...
0
votes
1answer
73 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-...
1
vote
1answer
84 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 ...
1
vote
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 ...
0
votes
0answers
18 views

Poisson data prediction with month variable

I have count data based on the number of failures per month. I have month, year, type of failure, and the count of fails. I have tried using R's glm package, ...
0
votes
1answer
44 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. ...
0
votes
0answers
16 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 ...
0
votes
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 ...
3
votes
1answer
56 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 ...
1
vote
0answers
169 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. ...
0
votes
0answers
6 views

Regression relating means and variances in DESeq2

In the DESEq2 algorithm for analyzing RNA-seq data for differential expression, a key hypothesis is that the means and variances of the count data, assumed negative binomial, for the individual genes ...
1
vote
0answers
19 views

Can I model incidence per 1000 people per month using poisson regression without an offset or using weights?

I am trying to model incidence rates (number of malaria cases per 1000 people per month) over time. I only have the data in the form of rates per 1000 people per month, i.e. I do not know the total ...
0
votes
0answers
21 views

How to combine count data and percentage data for ordination methods?

The system I have has multiple sites each of which was surveyed for biodiversity. Some species are too hard to count individually so we used percentage cover, others were easy to count so we have ...
0
votes
0answers
48 views

Is this usage correct for using isometric log ratio [ILR] transform with counts data (compositional)?

If one wanted to construct a simple pairwise correlation matrix from an compositional data table using an ILR transform preprocessing step, would this usage violate any assumptions with the transform? ...
0
votes
1answer
58 views

Measuring skewness of abundance over time

I have measurements of flower counts thru time for a bunch of species and locations. I'm interested in whether they are more or less "normally" distributed, with a peak in the middle and symmetric, or ...
0
votes
0answers
107 views

Fitting GLMM to roe deer count data with glmmTMB: workflow and spatial Autocorrelation

I'm fitting GLMM's to roe deer count data derived from GPS locations based on a regular sampling grid with R. From what I could tell glmmTMB seems to be well suited for this kind analysis - especially ...
4
votes
2answers
72 views

Count data time series for hospital emergency arrivals

i recently started to work in a hospital and we are interested in forecasting the arrivals to emergency; the only variable we have information about is the number of arrivals to emergency The time ...
2
votes
2answers
55 views

How do we compare count models for prediction and inference?

I have estimated a number of count models on a data, including Poisson, Zero-Inflated Poisson (ZIP), mixed-effects Poisson, mixed-effects ZIP and, a few different versions of each of these based on ...
0
votes
0answers
33 views

What's a good approximation to the count distribution of people for days of birth?

I have data on $n$ people's dates of birth and let's ignore the years and look only at the $k$ = 366 days of the year (including Feb 29). Assuming that dates of birth are uniformly and independently ...