logistic regression

  1. J

    Normal logistic regression vs a mixed model; which to use? benefits gained?

    I have some evidence to suggest that one vaccine was far superior over another and resulted in the local elimination of a disease. Because it affects pharmaceutical companies the information is sensitive so I will share as much as I can. I analysed the following data set using logistic...
  2. J

    Logistic Regression

    Hello, I'm currently working on a churn modelling exercise that uses logistic regression. The challenge that i'm facing now is that the model is not returning good results. My hypothesis is that the churn rate in my data set is too small, such that a logistic regression was not able to pick...
  3. S

    saving predicted probabilities in logistic regression w/ bootstrapping

    SAS allows you to bootstrap a logistic regression and then save the predicted probabilities associated with logistic model. When I try doing that in SPSS, I get the following message: "This command is trying to save new variables while bootstrapping is in effect. The new variables will...
  4. A

    1)Test multicollinearity b4/after Stepwise Log Regress? 2)Final Equatn 3)Model Select

    Hi all, I need to perform logistic regression for my study. Pretty new to it but have read up on it and have tried it on SPSS. I would like to seek the advice from all of you regarding it. A brief description on my study: I want to see which factors (categorical and continuous) are...
  5. C

    Have I correctly specified my model in glmer ?

    The following multilevel logistic model with one explanatory variable at level 1 (individual level) and one explanatory variable at level 2 (group level) : \text{logit}(p_{ij})=\pi_{0j}+\pi_{1j}x_{ij}\ldots (1) \pi_{0j}=\gamma_{00}+\gamma_{01}z_j+u_{0j}\ldots (2)...
  6. C

    How to compute the residual standard deviation from `glmer()` function in R?

    I want to extract standard deviation of residual from `glmer()` function in R . So I wrote : lmer_obj = glmer(Y ~ X1 + X2 + (1|Subj), data = D, family = binomial) sigma(lmer_obj) I noticed that the last command `sigma(lmer_obj)` returns always "1" irrespective of data ...
  7. C

    Interactions in logistic regression - Please help

    Hi everyone, Currently I'm writing my thesis on the effects of divorce on children. It's a complex design so I guess I'll be posting more questions here :) My dependent variable is whether or not the respondent has ever been in a relationship. My independents are 2 dichotomous variables ...
  8. B

    Need help choosing a statistical method/model

    Hello, I am currently doing a study on the defensive behavior of the European Grass Snake, and I was hoping someone could help me figure out which model to use to analyze my data. I have 3 categories of dependent variables - 1) Pre-Capture Behavior 2) Post-Capture Behavior 3)...
  9. C

    Estimating Multilevel Logistic Regression Models

    The following multilevel logistic model with one explanatory variable at level 1 (individual level) and one explanatory variable at level 2 (group level) : \text{logit}(p_{ij})=\pi_{0j}+\pi_{1j}x_{ij}\ldots (1) \pi_{0j}=\gamma_{00}+\gamma_{01}z_j+u_{0j}\ldots (2)...
  10. E

    Help with glm--- Simple Logistic Regression

    Hi All! Thanks for reading. I wanted to compare month of sample collection (April, May, June, and July) to presence/absence data (coded in binary dummy variables). I tried to run a Simple logistic regression, but realized that the output table with p values, etc all report for may, June, and...
  11. H

    Logistic Regression as Data Transform?

    Hello everyone, new here, glad to be here! I have what might be an unorthodox question. I use the matlab function 'mnrfit' http://www.mathworks.com/help/stats/mnrfit.html to compute a logistic regression model given input data. The matlab function 'mnrval' performs the inverse...
  12. Q

    Using single items as predictors for a logistic regression

    Hello! I'm conducting a logistic regression analysis for a project that has an absolutely awful research design, and I'm considering removing the regression altogether. But just out of curiosity, say I have 4 different predictors in my model. If one of these predictors is ONE item within a...
  13. Y

    Reporting logistic regression results

    Hi, I have a study that aims to find out the association of a binary outcome (e.g. BP control-Y/N) with categorical independent variables e.g. their dietary and exercise preferences. As I have a very long list of these independent variables (50 qns on dietary and 50 qns on exercise), do I...
  14. A

    Logistic regression and significance of continuous variables across 3 periods

    I'm currently working on a logistic regression analysis in R with a binary response variable (0 = non-used; 1 = used location). I am modeling non-random habitat selection for a species of wildlife. I recently ran into an issue where I need to evaluate non-random habitat selection across 3...
  15. E

    Comparing groups/sites---need advice identifying variables and appropriate tests

    Hi, thank you for reading this and your potential input. This is a research study. I examined the prevalence of parasites in one insect species in an island ecosytem. Insects were collected from: Island 1: 3 sites (all very different elevations) Island 2: 2 sites (similar elevation)...
  16. R

    Making sense of the parameter delta in this equation.

    Hello, I was reading this paper about pollen dispersal directionality and I am trying to make sense of the so-called directionality parameter \delta The Statistical Model On pages 4 and 5 they explain their analysis under the section `statistical procedure`. More specifically, in the first...
  17. R

    Making sense of the directionality parameter

    Hello, This post has been cross-posted here. I fail to delete the current post to leave only the other post open. Feel free to delete this post if you can do that. Note: The following greek letters and equations are written in LaTex. I was reading this paper about pollen dispersal...
  18. K

    [SPSS - Logistic Regression] Resolve the linearity of logit assumption

    I am running a logistic regression and my income variable violates the linearity of the logit assumption. It is not negatively effecting the goodness-of-fit statistics. I have transformed the variable into a log but that impacted the constant and made the odds ratio explode. When I square...
  19. D

    Ordinal dependent variable - regression help!

    First of all, I am a complete newbie to stats from a non mathematical background, but I need to analyse survey data for my dissertation! So I have a dependent variable that is ordinal - it's a 5-point likert item (strongly disagree - strongly agree). My independent variables are composite...
  20. V

    Logistic Regression model: a significant predicting variable with low sensitivity?

    Hi fellow forum members! Thank you in advance for your time! I used binary logistics regression (SPSS) to determine the relationship between ambient noise levels (a continuous variable on a logarithmic scale, dB) and a single dichotomous dependent variable ("yes" - 1- for whale positive...