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 ...

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Negative Binomial Anscombe Residuals

I need a help :) I'm working on a Generalised Linear Regression model, using the 'so called' NB2 model, in other words I'm using the Negative Binomial regression for count data. I would like to graph ...
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13 views

Help in determining prediction accuracies over the life of a customer

I have been tasked with determining the accuracy of some data, however my statistical knowledge is weak and I am hoping to be pointed in the proper direction. For a customer, we have a series of ...
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1answer
17 views

Which models for suitable for integer values of independent and dependent variables

The data set has independent and dependent measurements that are events, and can be counted. What input / output models are appropriate for integer values? So far I've tried linear regression, and ...
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3 views

Correlation between offset and predictor in count data

I am fitting a Poisson model that requires an offset term to account for sampling effort. However the offset term is highly correlated with one of the linear predictors that is central to my ...
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19 views

R implementation of Zeger's parameter-driven (latent process) approach to time series regression with count data

For time series regressions with count data, Poisson-response with log link (i.e. GLM) is widely used. However, such models often suffer from serial correlation. One approach to handle was introduced ...
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2answers
49 views

Appropriate method for determining difference between means?

I'm looking at the calling rate of bird species when prey availability is altered. So there are two groups, a control (no manipulation) and experimental group (where prey has been increased). I'm ...
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12 views

What test should I do to evaluate overlap between two sets of count data

I have one set of data. This set A has about 5000 members and they are divided in 8 subgroups, but each member has also a membership in one out of 24 other groups (let's call these set B). What I want ...
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21 views

Does N-1 correction for Pearson's Chi-Square apply to r x c tables generally?

Campbell (2007) recommended what he called the "N-1" correction for chi-square tests performed on two-by-two contingency tables. He described the correction as: "the K. Pearson chi-squared test ...
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1answer
60 views

How to interpret ANOVA output when comparing two nested mixed-effect models?

I've got two models (all variable are count variables): ...
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0answers
10 views

Simulation of CI of amount of values in different intervals by adding noise to original data

I am having a hard time trying to solve this problem, so maybe some of you guys can sort it out. I have a large data set containing a value describing the thermal comfort in buildings called PMV. The ...
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2answers
59 views

Alternative for Fisher's exact test for count data in table bigger than 2x2

I have count data on different languages from comparable corpora. It looks something like this, where the counts give the number of clauses with that particular word order attested in each language ...
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19 views

Good way to categorize count data?

I want to use some count data to train a classifier. The count data range from 0 to 400 something. There are a bunch of smaller counts (0's and 1's). I wonder what would be a good way to categorize it ...
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70 views

Count data in a Structural Equation Model

I am currently trying to fit a structural equation model (SEM) on a certain dataset using R (lavaan package). Some of the most important variables in my model are count data (abundance of different ...
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13 views

What is the number of “observed data” in a multivariate HMM

I am trying to calculate BIC scores for a couple of models with different states. (See general question 1 and a more specific q2 - no answers in either). I've done my own research a little bit and ...
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0answers
18 views

How to compare a one-day count against a historic mean to identify an external change

A few months ago a client's website had some good press and their daily site visits spiked. Now, every time their traffic shows a bump, they think something external has caused it to happen. I'm ...
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1answer
80 views

How to compare count of two groups?

I have a two groups of data - 1/ All data and 2/ Selected_season, which is only some subgroup of all data. I want to find out: a/ if proportion of BM, HB, etc. groups is the same in All data and ...
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2answers
46 views

How to do smoothing of data with low counts?

We are a facing a problem of fluctuating shares for each week for the products we are studying due to low counts. e.g. If we have 4 products and for each one we have say like 5,8,3,6 details and we ...
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1answer
70 views

How to model a count dependent variable with upper limitation

I have a dependent variable, which have 0, 1, 2, or 3 for its value. I asked participants to choose three items and coded 1 if it is in a certain category and 0 otherwise. I add the three binary ...
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1answer
93 views

ANOVA and Count/Percent Data

I'm just starting to work with some count data and I'm still trying to understand some of the complexities of it, so any help would be greatly appreciated. First the simple version, and then the ...
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1answer
33 views

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 ...
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2answers
62 views

Best distribution to handle a ratio of counts as a response variable

A quick statistics question (apologies for the added biology): I have two sets of counts (for the expression of two different isoforms of a particular gene), and to generate the response variable in ...
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0answers
38 views

Detecting a significant change in the difference between two rates from T1 to T2

I asked this previously but I failed to activate my account so I was not able to respond to comments and my question was never answered. Here is attempt 2: I have two rates of compliance for two ...
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0answers
15 views

are the percentage differences significantly different from oneanother?

morning, say i have 5 wheat varieties undergoing 2 treatment. when counting the seeds of the replicates the percentage difference between the means of the 2 treatments is 10% for variety 1, 30% for 2, ...
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16 views

Comparing transaction counts between samples

I have a treatment group and two control groups for customers and the count of their transactions: ...
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1answer
62 views

Categorical variable as response in poisson regression

I have data on damages on flowers from different treatments. The damage was originally count data (number of damages per flower) but the person collecting the data categorized the data in four levels ...
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0answers
55 views

does the equivalence of Poisson and conditional logit models hold for fixed effect panel data and negative binomial models?

Guimaraes et al. (Rev Econ Stat, 2003, 85/1) describe the conditions under which the results from poisson regression models and conditional logit models are equivalent. I am trying to find out whether ...
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17 views

How to model occurrence counts in groups with latent membership?

I have a dataset that describes the daily history of occurrences of a certain phenomenon P among a certain population. (These are subdivided into certain classes or forms that the phenomenon can take: ...
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113 views

Count data correlation

My dataset is basically a time series - each case is a one day and several events are being observed for each case. I am not experienced in time series analysis but I still would like to get at least ...
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1answer
46 views

Is the Durbin-Watson test appropriate for count data

In determining if there is any serial correlation in a time series of count data, is the Durbin-Watson statistic or similar approaches appropriate? I ask this question because the dwtest implemented ...
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28 views

Modeling Counts With Small Observations

I am new to Cross Validated SE so I am going to try and formulate my question to the best of my ability. I have a large data set that contains $5$ different fields. The fields are ...
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0answers
39 views

10% dip in February for metrics that count?

February usually has 28 days, unlike it's neighbors January and March which have 31. It seems that most countable things will exhibit, on average, a 10% dip in February for the missing 3 days. This ...
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1answer
62 views

Should a Poisson regression be carried out with only 3 data points?

I'm trying to test the relationship between the number of adults counted and the percentage heather cover over 3 areas. The data looks like this: ...
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1answer
161 views

Is it possible to statistically test relationships between counts and percentages?

I have counted adult butterfly numbers over 3 areas and would like to compare these counts with the percentage heather cover on each of the 3 areas. Is this possible? My data looks like this (the ...
2
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0answers
146 views

Estimating abundance using non-normal count data

I have sample counts of $n=20$ or $n=7$ taken from right-skewed and zero-inflated populations. The challenge in each case is to use the sample to estimate the total count in that population. Each of ...
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50 views

Can Principal Component analyses be applied to a counting trait?

I am analyzing a segregating population of plants coming from an hybridization process. The experiment consists in several field plots (according to an augmented design). In each plot a segregating ...
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1answer
53 views

What is a good way of testing for a relationship between two count variables?

I have counts of occurrences of two types of words (A and B) in several texts. What I would like to test is whether the frequencies of occurrence of both types of words across texts is 'correlated'. ...
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47 views

Nonparametric test for largely skewed count data

My research design looks as follows: an experimental game with 4 participants (human subjects), repeated for 20 rounds. During each round, participants are allowed to form bilateral coalitions which ...
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64 views

Poisson regression on the means of count data

I just finished a small research project about hummingbirds and the effect of hummingbird feeders. I am a bit unsure about how to proceed with the statistics. We placed 15 points in a distance ...
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1answer
32 views

Regression when the value of one independent variable is dependent on another independent variable

I need to predict the number of retweeets a tweet receives as a function of (1) whether there is a hyperlink within the tweet's text and (2) the position of the hyperlink within the tweet. If a tweet ...
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2answers
59 views

Predicting zeros with count data model

I'm working with count data (ticket sales, to be specific) and I'm having trouble fitting a model to it. I've tried a linear one and a transformed linear one, but the residuals end up being non-normal ...
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0answers
39 views

is Julian day a count data or a continous data

A stupid question but has confused me. My dataframe looks like this: ...
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1answer
42 views

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 ...
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9 views

Modelling biases in selection of one choice from many using count data

In a biological experiment I draw somewhere between 100k and several million datapoints, where each datapoint is one of 1024 DNA sequences. If each sequence has an equal probability of coming up, I ...
2
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1answer
21 views

I got a good OLS fit for integer variables, do I still need to use count data methods?

First of all, I'm not a statistician, but I'm teaching myself some methods I require for a project I'm doing now. I have a 2D dataset of N observations. For the ith observation, the first entry is ...
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0answers
40 views

Mixing distributions to model parameter errors in Poisson

I'm trying to fit a complex model to count data from a detector. I have background and background+signal data. My goal is to obtain information from the signal by fitting a Poisson with $\lambda = ...
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1answer
83 views

Count data model validation

I'm using different models to model count data, the purpose of modelling is prediction. Values vary from 0 to 7. I try to use cross-validation method to assess out-of-sample predictive perfomance, but ...
2
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0answers
20 views

Using Resampling to understand a large table

I have a data set that is very large. The attributes (columns) are several thousand. Some are sparse others are not. Some are ordinal, others interval, nominal or ratio. The row size is 10s of ...
3
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0answers
53 views

Evaluate deviation from negative binomial model

I'm trying to figure out how to determine to what extent a sample deviates from a negative binomial model fitted to a larger population. As an example, I generated counts of doctor visits for a ...
2
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0answers
192 views

Standardizing count variables in panel data with overdispersion - R or Stata

I'm running a regression where the dependent (response) variable is a highly dispersed (slightly zero-inflated) count and the explanatory (independent or predictor) variables are continuous, counts as ...
2
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1answer
136 views

GLM for count data

I ran an experiment with an eye tracker and my data frame has this look: ...