Statistical Analysis Stack Exchange
Statistical Analysis Stack Exchange

Questions tagged [count-data]

Count data are non-negative integers representing whole amounts.

When such data are the dependent variable in a regression, Poisson or negative binomial regression may be appropriate methods. One common problem is "zero-inflation" (where the proportion of zero values is greater than predicted by a distributional function); there are various models for dealing with this.

Wikipedia https://en.wikipedia.org/wiki/Count_data has an article with further references.

959 questions
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Fractional dependent variable: Why not use Poisson regression?

In many settings, we are interested in estimating a model with a fractional dependent variable. For example, Papke & Wooldridge (1996) http://faculty.smu.edu/millimet/classes/eco6375/papers/papke%20wooldridge%201996.pdf consider 401(k) plan…
Felix H
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How to find the sweet spot

In R I have data where head(data) gives day new_users promotion 1 33 20.8 2 23 17.1 3 19 1.6 4 37 20.8 Now day is simply the day (and is in order). promotion is the…
Ole Petersen
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Comparing Counts Between Two Independent Groups

I have 2 groups of patients and I'm looking at what percentage were discharged from the hospital at different time points after surgery. Day 1 Day 2 Day 3 Day 4 Group 1 12% 10% 25% 12% Group 2 50% …
area51
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count data that does not follow poisson distribution

Im analysing count data (number of clinic visits) when I test for poisson distribution using 1 sample KS test in spss the sig is <0.05( meaning it doesnt follow poisson distribution ) it does not follow normal distribution either, no values of…
maryam
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What distribution should I use to model bounded count data (that also feels a bit like a proportion)?

I am trying to determine the correct model for my data. I want to model the effect of two categorical independent variables (and their interaction) on my outcome variable. I am using SAS (proc genmod, probably). The outcome variable can range from…
EmMa
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Statistics for a Particle finding experiment?

I am running an experiment where I use software to count the number of particles on a filter. The software is not always perfect and has different parameters etc. that I can set, I am also using different backgrounds to improve contrast. There can…
torchern
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Normalize counts over time without adding excess variability

I'm not quite sure if this is possible to do, but I have count data that I would like to put on a similar scale in order to compare it. We are tracking where people go, and want to see if people who attend a certain event significantly change where…
Steven
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compare whether 3 factors of a categorical variable are distributed differently

For every subject in a study, I have 40 responses that can be: a,b,c. So it would look somthing like sub | trial | resp 1       1        a 1       2        b .... 50     40      c I want to check if their…
Paris
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Is FDI per capita a count variable?

I was wondering if it is possible to state that FDI-Foreign Direct Investments, per capita is a count variable? By definition count variable is number of accidents, number of suicides. So theoretically FDI per capita is also considered to be a count…
Romas
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What test would be appropriate for a table containing data on number of visits for several individuals?

I have a table containing rows with count data for several individual animals. The counts represent the number of daytime visits that the individual animals made to a site over many days. I have divided each day into 10 discrete one-hour periods…
Bruce E
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converting to count dependent variable

I am working on a paper that tests to see if banking competition has an impact on whether borrowers engage in relationships with multiple banks. Number of relationships with various banks obtained from the survey : Eg firm (a) 1 relationship with a…
Naveed Ahmed
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Confidence level of a sample of count data

I have a sample of count data (N = 226) representing a parameter of a population. The sample contains many zero values and a few non-zero values. How can I best estimate the level of confidence that the population is being truly represented by this…
user100124
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Statitical test on count data

I have a questions regarding a statistical analysis of a biologic experiment. In the experiment I have collected imaging data on the duration of contacts between immune cells. We have compared two distinct types of immune cells and their contact…
immunogen
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Scaling count data by population size and area

Let's say I want to count the number of people in 10 different counties that have $x$ characteristic. As each of the 10 counties have different population sizes and areas, I want to scale the count data by population size and area. Is this the…
luciano
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