Linked Questions

5
votes
1answer
5k views

Interpreting Poisson output in R [duplicate]

I am having some issues with interpreting the results from a Poisson log linear model done in R. I will give my thoughts and it would be great if somebody would be kind enough to expand on it. I just ...
0
votes
1answer
817 views

intepreting Negative coefficients of Poisson model [duplicate]

i have fitted a Poisson regression to my claim frequency data. my predictor is make of vehicle. I have obtained the following result: ...
0
votes
1answer
123 views

Interpreting estimates from generalized models in R [duplicate]

I'm using R to run some generalized linear models (GLM) and I want to interpret the estimates. If I use a GLM assuming Gaussian distribution with identity link, interpretation is easy: if the ...
0
votes
0answers
10 views

How to interpret the resulting negative regression coefficient? [duplicate]

How to interpret the resulting negative Poisson's regression coefficient? I am investigating the effects of environmental factors on mortality. A negative regression coefficient means feedback (proves ...
13
votes
2answers
22k views
18
votes
1answer
5k views

Goodness of fit and which model to choose linear regression or Poisson

I need some advice regarding two main dilemmas in my research, which is a case study of 3 big pharmaceuticals and innovation. Number of patents per year is the dependent variable. My questions are ...
1
vote
3answers
2k views

Statistical test in R for count data

I am struggling with using the correct test for count data in R. The dataset I have is the number of nymphs produced by three aphid species on wheat. So this is count data with one response variable (...
2
votes
1answer
1k views

Interpreting Poisson regression coefficients

I'm having a little trouble interpreting regression coefficients from a Poisson model. Wooldridge, for example, says: "The Poisson coefficient implies that $\Delta_{pcnv}=.10$ reduces the expected ...
6
votes
0answers
4k views

Poisson regression for binary data

I've been trying to read up on Poisson regression models, and it looks like it is possible to estimate such a model with a binary outcome. This has come up before on this site here (and somewhat here ...
2
votes
1answer
2k views

How to interpret coefficients in a Poisson regression with interaction terms?

This question is a prolongation of this question: How to interpret coefficients in a Poisson regression? If we follow the (almost) exact same routine, but we add correlation between the variablese ...
4
votes
1answer
2k views

How is the intercept calculated in a generalized linear model and why is it different from a linear model?

I have a set of count data that I have fitted both a linear model to and a Poisson generalized linear model. The mean of the raw data is 233.375 and the standard deviation 279.983. I have been ...
3
votes
2answers
623 views

Incident rate ratios with log-transformed variables in Poisson regression

I'm in a bit of a mess with interpreting the output of a Poisson regression model with log-transformed predictors. The predictors are counts, and the log transforms them for the linear part of model. ...
1
vote
1answer
349 views

Interpretation of Coefficient

In Poisson Regression, suppose we have the following regression equation: $\ln(E(Y_i|X_1)) = \beta_0+ \beta_{1}X_{1}$ where $Y$ is the number of heart attacks. Also suppose $X_1$ is a binary variable (...
0
votes
0answers
1k views

How to interpret and explain negative coefficients when they do not make sense

I have seen appearance of negative coefficients where they do not make sense (the data is related to costs where negative coefficient should not appear). If regression models are fitted to individual ...
1
vote
1answer
94 views

Is Poisson regression a good fit for this dataset?

I am using a hurricane dataset (specifically the NDAM and Gender_MF columns): ...

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