13k views

Understanding complete separation for logistic regression [duplicate]

Why does logistic regression not converge for a linearly separable data set? For linear separable data sets the model parameters go to infinity when mimizing the error function (according to ...
2k views

Logistic Regression: p values all '1', yet model fits perfectly [duplicate]

I was trying to help a student and was foxed by this Logistic Regression problem and seek your explanation. Here's some economic data. All we have to do is create a model to predict whether the ...
4k views

Large value of exp (B) in binary logistic regression SPSS what is wrong? [duplicate]

I had a very large value for Exp(B) in SPSS binary logistic regression. What is wrong and what should I do?
1k views

How to tell which variable is perfectly separated in R [duplicate]

I am running a logistic regression model in R using glm. I received a warning that complete separation occurred. How do I determine which variable is causing this? R doesn't tell you what variable is ...
755 views

Logistic regression in R ; glm.fit: fitted probabilities numerically 0 or 1 occurred [duplicate]

I'm fitting a logistic regression model in R. Following is the structure of my data set. I've used the glm function in R. ...
378 views

How to deal with separation in logistic regression? [duplicate]

I'm running a binary logistic regression on 15 independent variables for 180 observations in Stata (version 11). This I do for four different groups, i.e. four dependent variables. For three, it works ...
245 views

How to deal with a model that can't be fit due to quasi-complete separation? [duplicate]

I am doing a binary logistic regression analysis. I got one categorical predictor with 7 levels. When I try to do this in Minitab 17 I get an error message: "The model could not be fit. Maximum ...
227 views

binomial GLM output hugely affected by a factor level with all zeros [duplicate]

I’m trying to estimate the effects of pest control on rat abundance, but I'm finding that the inclusion of a pest control category that contains all zeros is having huge effects on the results. My ...
179 views

Large coefficients in logistic regression [duplicate]

This is from the book The statistical sleuth--A course in methods of Data analysis Chapter 20, Exercise 12(c)-(e). I am using logistic regression to predict carrier with possible predictors ...
126 views

logistic regression - complete/quasi-separation [duplicate]

What is the implication if I don't fix a logistic regression that has complete or quasi separation? can I still read the marginal effects or are they not going to be valid? My exercise is actually ...
102 views

GLM for proportion data in r - with many zeros (or ones) [duplicate]

My understanding is that generalized linear modeling (GLM) is recommended for proportion data. However, this seems to run into problems when a set of data is full of zeros (or ones). For example, a ...
68 views

Logistic Regression Get 100% R-square but no predictors are significant? [duplicate]

How could that be possible? The model is significant too. The null model already predicted 70% correctly. After adding predictors, the model predicts 100%. But no single predictors are significant. I ...
53 views

Logistic regression not converging [duplicate]

I run a multivariable logistic regression in SAS using the main effect/independent variable as continuous and categorical. As a continuous variable the confidence intervals of the odds ratios were ...
49 views

extremely strange logistic regression results [duplicate]

I am very new to r and statistics so excuse me if the answer to my question is very obvious. I have surveyed 64 people on their Facebook behaviour related to their political participation. One of my ...
32 views

Dealing with Complete Separation in Logistic Regression when Reporting [duplicate]

I have a question regarding how one would deal with complete separation in logistic regression when reporting the outcome for statistical analysis. For a study, we have group participants into 4 ...

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