# logisitic regression

1. ### Logistic regression, sample sizes and bootstraping

Hello, this is my first post. I currently I'm working in my phD in a multivariate logistic model but I have a problem regarding the sample size of my observations: -The "success" (1) event group has a sample size of 249 distinct observations - The "non success" (0) event group has a sample size...
2. ### Positive chi-square test: what to do next?

Hi!! I'm analysing two categorical variables, Landslides (YES/NO) and Vegetation (grouped into 18 classes), and I'd like to explore and model the relationship between them. Firstly, I've carried out a chi-square test for independence that has returned a positive result, i.e. the two...
3. ### Suggestions for Statistical Methods for Health Research

I am currently planning a research project looking at a scoring system for patients (using demographics, social circumstances) to determine whether there is a relationship between a patient's score and their length of hospital stay. The score has 5 domains which are all equally weighted so...
4. ### Model selection for logistic regression, comparing p-value approach, BIC and CV.

Hi, I need to write a discussion on three approaches of model selection; p-value, Bayes factors (using BIC) and leave-one-out cross validation. The p-value is not preferred, statiscal significance depends on sample size, p-value is based on imaginary data, depends on the intentions of the...
5. ### Should I include this variable or not?

Hello, My dependent binary variable is Turnout in 2010 elections (yes/no) and I'm performing logit analysis using a cross-sectional dataset. There's a variable though called Past vote in 2005 elections i.e. (Abstain,Conservative,Labout,etc) and, as we expected,its high correlated with...
6. ### Interaction effects of nominal and ordinal variables on binary dependant variable

Hi! I'm doing an analysis of interaction effects of one binary nominal variable (medication used), one ordinal variable (duration of therapy ; 1-few weeks, 2-less than 3 months, 4-less than six months, 5-more than six months) and one interval variable (age) on binary dependant variable (0- does...
7. ### F-test equality coefficients same model

Hi, I have binary logistic model with only binary independent variables (which were originally 3 multi-valued nominal variables). For example, 4 of the binary independent variables are price_1000, price_2000, price_4000, and price_5000 (price_3000 being the base).. How do I test whether...
8. ### Help! my model isn't predicting any yes outcomes and don't know why

I am producing a logistical regression analysis to find a model to predict whether someone has minor mental health problems or not. I'm almost certain i've coded all my data correctly but no matter which variable I put into the model it doesn't predict any yes outcomes. my classification table...
9. ### Logistic regression

Hello everyone... I'm trying to create a graph similar to the FIG. I did the analysis in proc logistic and I found a quadratic effect and I created the graphic, But I don't know how to calculate the maximum predicted value and the confidence interval. Thanks so much in advance for...
10. ### measuring interaction effects

I've spent months studying statistics texts, and I just cannot figure out how to do the following: I've got categories distinguished by some characteristic, say M vs. F, and then each of those categories has been assigned to one of two groups, say the treatment and the control group in an...