Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

Filter by
Sorted by
Tagged with
1
vote
0answers
14 views

Is it valid to manipulate the unit of time for Poisson distributed counts?

If I have discrete count data measured in minutes (60/minute) that does not fit the Poisson distribution (variance >> mean), is it valid to increase the granularity of that data to seconds if it evens ...
0
votes
0answers
7 views

JAGS with dependent observations

I have the following model. At every time unit, the arrivals are Poisson. With a Bernoulli probability, I observe either zero of these arrivals or all of these arrivals. If I don't observe anything, ...
1
vote
0answers
29 views

How to estimate a proportion as a step function of time

There is a black-box mechanical process that, at any time, may be either succeeding or failing. It is known that after an initial disturbance, the process will fail $X\%$ of the time for $N$ seconds, ...
0
votes
0answers
6 views

Statistical modeling of count data in different regions

I want to statistically model the likelihood of accident categories in different regions. All accidents happened in the timespan of one year. I think I can demonstrate the problem best by reproducing ...
0
votes
0answers
11 views

Help with multivariate analysis

I'm looking for some guidance on a multivariate analysis that I am trying to run on my data. For context, my response variable is counts of abnormal behaviours displayed during [~60] observation ...
1
vote
0answers
17 views

Negative Binomial vs. Discrete Survival

I am trying to model a discrete duration variable (number of weeks) and I am not sure which model to use. Many would argue that durations are modeled using survival models. However, in J. Hilbes ...
0
votes
1answer
24 views

Multicollinearity for Offset Variable?

In a Poisson model, do we need to check for multicollinearity between the offset variable and other covariates? For example, if I offset by population size, would it be problematic to include ...
1
vote
0answers
14 views

Modelling count data with extreme underdispersion - what distribution?

Suppose we have some count data, and we want to use a model that allows for "overdispersion" or "underdispersion" in the data (i.e., higher or lower variance than the Poisson distribution). Let $X$ ...
0
votes
0answers
11 views

Statistical tests for periodicity in a histogram

I am trying to analyse the distribution of pairwise distances between data points distributed on a circle. In particular, I am interested in determining whether there is any periodicity in these data....
1
vote
0answers
19 views

Statistical test to compare predictive measures with count data

I'm reviewing a paper that compares predictors of healthcare demand in terms of hospital visits for several conditions. The authors have used a Pearson's rho to determine which is best, and further ...
0
votes
2answers
31 views

How to identify outliers in a zero-inflated binomial distribution of count data

I have some data in which the researchers measured the number of times someone lied on a particular day (n=1000). I would like to identify outliers- those people who lied much more than the rest of ...
0
votes
0answers
24 views

Is a continous distributions valid when modeling count data? And vice versa? when n is high

When looking at the shape of the histogram of a dataset, I always have difficulty discerning if I should model the data based on Poisson or Exponential distribution, as both seems reasonable. Based ...
1
vote
1answer
23 views

Panel data or separate regression models on count data

I'm trying to find the best way to model count data collected over three years. I have data representing the number of complaints pre-schools in one city has received for the years 2017, 2018 and 2019....
1
vote
0answers
33 views

Cox model appropriate for my time to event problem?

I am trying to estimate the factors associated with delay in implementation of a policy. I am analyzing the delay, measured by number of days, it took an entity to implement one of three policies, ...
0
votes
1answer
31 views

Bayesian Statistics - How to weight a Poisson distributed response

I have a Bayesian GLM where the response that I'm interested in is count data. I want to weight the the response by the variance to account for uncertainty in the measurement. If the response was ...
0
votes
2answers
53 views

Is SAT score a count variable?

It can't be continuous because you can't get a decimal SAT score, right?
0
votes
0answers
30 views

Can I use Chi square test with the mean of averages instead of total?

I simulated a network-on-chip with different parameters that affect the performance and I'm trying to stablish relations between the parameters. Below I have the average delays for different buffer ...
0
votes
0answers
6 views

handling spatial auto correlation of case level data in areal units

I'm looking at spatially modelling count data of number of student posts made to an online discussion board for a massive open online course. I have student level data, where the students have ...
0
votes
1answer
17 views

Probability as a function of age from observations over several years

Hoping someone can help me correct the flaws in my logic. I have a number of water tanks, which may leak. I want to model the probability a water tank leaks given that it has never leaked before as a ...
1
vote
1answer
33 views

Analysis of time series data with peaks for counts of occurrences

I have time series data that measures the occurrence of insects ona weekly basis during a certain period of several month during several years at several locations. Depending on the insect species and ...
2
votes
2answers
52 views

Hypothesis testing intervention analysis - pre vs post with expected seasonal change

I have 400 discrete geographic areas of vastly different sizes, where I am recording the number of specific events. Every event is timestamped so I can summerise from daily counts to weekly, monthly, ...
1
vote
0answers
23 views

Bivariate copula for count and continuous variables?

I'm interested in fit a Copula from my bivariate data with a count variable $Y_{i}$ and a continuous one $X_{i}$. So, let $F(x)$ and $G(x)$ be the margins for the mentioned variables and $C$ the ...
2
votes
1answer
32 views

Interpretation of zeroinfl vs. glm.nb results

I am trying to test effects of 3 predictors on overdispersed count data with many zeros, and a Vuong test suggested that a zero-inflated neg. binomial model would fit better than a negative binomial ...
1
vote
0answers
15 views

Appropriate model for count data when response variable minimum value is far above zero

CASE 1: I am trying to model count data; the response variable, y=c(12, 15, 34, 13, 12, 33,....,45) while the explanatory variables are location (binary, rural/urban), marital status, education level, ...
3
votes
2answers
57 views

modeling response variable that is proportion

I am attempting to model data where the response variable y is a proportion (ratio of counts=successes /(successes+failures) in the range (0,1) the predictors are ...
0
votes
0answers
20 views
2
votes
1answer
26 views

What test do I use for comparing count data for significant differences between two groups of different sizes?

I need to compare count totals between two groups that are of unequal sizes. For example see table: Total injuries includes back/neck injuries. I am looking to see if the back/neck injuries are ...
0
votes
1answer
33 views

Comparing time series trends of non-linear count data across multiple firms in R

I have data on the number of patent applications per year for 20 years for ten different firms. I am trying to answer the question, "did the number (count) of applications evolve differentially across ...
0
votes
0answers
7 views

Dealing with count data as both the dependent and independent variable

I have a data set that I want to run multiple tests on, one with the count data as the independent variable in a regression and one with it as the dependent variable in a regression. The count data ...
3
votes
1answer
26 views

Looking for a discrete distribution with a specific mean-variance relationship

Say we have some counts $Y$ for which the mean-variance relationship is $$ Var[Y] = \alpha E[Y] + \beta E[Y]^2. $$ From this, we can say that: If $\alpha = 1$ and $\beta = 0$, then $Y$ can be ...
1
vote
0answers
40 views

Distribution when count data have no zero counts

My data are monthly counts of samples submitted to a laboratory for testing. The data have no monthly counts of 0 for when no samples were submitted. How should this data be handled? What distribution/...
1
vote
1answer
23 views

Difference in proportion across study types based on count data from multiple studies?

We have the following situation. We have collected count data from a number of studies. Specifically, we looked at the number of people of each race in each study's cohort. We also collected a number ...
0
votes
0answers
21 views

Can I treat count data as continuous in Quantile regression?

I have data with the response is the number of dengue disease incidence per year from 2013-2019. The number of incidence per year is a big number, many values of 1000, minimum values is 228. I am ...
0
votes
0answers
18 views

Two intercepts for zero-truncated negative binomial model using VGAM

I am trying to understand the first and second intercept for the zero-truncated negative binomial regression model I estimated using VGAM. Below is my syntax: mod.negb <- vglm(ED_Visit ~ Male + ...
0
votes
0answers
11 views

How can I compare coefficient values from two different count models based on the same variables?

I'm running two quasi-Poisson models with the exact same variables, but on samples from two different countries. I'm doing this because I'm particularly interested in seeing whether the relationship ...
1
vote
1answer
39 views

Count data that has two peaks. How would I model this?

We did an experiment where people came in the lab and engaged in a helping task. They were told they could help with as many puzzles as they wanted to and a peer would finish them. The DV was the ...
0
votes
0answers
8 views

Test if counts in two conditions are significantly different without knowing the population size

The data are counts of cell structures in different (independent) conditions. For N cells per condition, in which N is different for each condition and unknown, the total number of X and Y structures ...
0
votes
1answer
37 views

Count Modelling and Rates and Zero Inflation

I am looking for some help modelling overdispersed (zero-inflated negative binomial) count data as a rate. I want to model the survivability of villages in different municipalities given guerilla ...
2
votes
1answer
35 views

Why use an offset variable as a predictor instead of just converting outcome to a rate?

I am reporting the results of an analysis where we tested the effect of various demographic predictors on the number of counselling sessions undertaken by participants during a clinical trial. I ran a ...
0
votes
1answer
25 views

Accounting for large absolute differences between entities in panel data regression

I want to estimate the effect of weather on business success by using a a panel data regression. My dependent variable is the daily number of visitors for different entities (for example amusement ...
0
votes
1answer
23 views

How to interpret the regression co-efficient of a particular variable in a negative binomial regression?

I have the following regression equation with a count variable as the dependent variable and diversity as the predictor. ...
0
votes
0answers
17 views

MCMC when intervals are irregular

I have a count model that has irregular intervals. It's a collection of some events throughout a year. The data is confidental so I cannot present the actual data but it has the following structure. ...
0
votes
0answers
7 views

Change in sign of price coefficient between OLS and 2SLS regressions?

I am hoping to estimate demand through two primary specifications, OLS and IV, where the dependent variable is the count of purchases and the primary righthand-side variable is price. In the OLS ...
0
votes
0answers
55 views

Modelling count differences on irregular lattice

I have the following dataset. I have a time series over an irregular grid where for each position in the grid, there is a variable that for each point in time counts the cumulative difference between ...
1
vote
2answers
89 views

Is there a statistical test comparing two distributions?

So I have a bar chart with x-axis: microRNA base additions (+1, +2, +3) and y-axis: microRNA counts of patients (each dot is a patient). I would like to compare distribution of base additions for ...
0
votes
1answer
37 views

Poisson Regression with overload of zeroes SAS

I am testing different models for the best fit and most robust statistics to my data. My dataset contains over 50000 observations, approx. over 99.3% of the data are zeroes - such 0.7% are actual ...
1
vote
0answers
14 views

Individual Item Probability From Forecasted Counts

My data is a time series, in which I need to be able to predict which day and hour an occurrence of an event is most likely to occur. To answer this question, I have constructed a SARIMA model on the ...
1
vote
2answers
41 views

Negative Count Variables in Data — modeling migration

I'm trying to explain migration rates in Europe with my regression using pca/pcr in glm. Of course some of the count data has to be negative in regions people move out of. This presents a problem for ...
0
votes
1answer
43 views

Negative Binomial regression: effect of scaling input data on model's output

I have implemented a neural network for time series forecasting. The time series consists of count data, so I chose to model it with a negative binomial distribution. My network is an autoregressive ...
0
votes
0answers
33 views

Should I treat the dependent variable as count variable?

In a study of crowdfunding, I am investigating the effect of the reputation of a person seeking funding for a project (a continuous variable) and ...

1
2 3 4 5
15