Linked Questions

3
votes
2answers
637 views

Power analysis for logistic regression with dummy independent variables [duplicate]

Per reviewer request, I need to do power analysis for a logistic regression model with multiple dummy variables. I have four groups: Control, (Treatment) A, B, and C. The hypothesis is that group A ...
1
vote
0answers
2k views

Sample size for logistic regression with categorical independent variables [duplicate]

Trying to find a sample size for logistic regression I found a rule of thumb in http://www.medcalc.org/manual/logistic_regression.php I cite: Sample size considerations. Sample size calculation for ...
0
votes
1answer
488 views

Is there a relationship between number of covariates and sample size in logistic regression? [duplicate]

Is there some definite relationship between number of covariates and the sample size in logistic regression? (e.g. larger the number of covariates, larger the sample size needed, etc.) Thank you,
1
vote
0answers
778 views

Power Analysis for Logistic Regression with one nominal variable [duplicate]

How do I estimate sample size or do power analysis for logistic regression with one nominal independent variable? Is there a way to do it with Stata?
0
votes
1answer
585 views

Need help determining sample size for logistic regression [duplicate]

I need help determining the sample size necessary for a logistic regression (binary DV) with two continuous predictors and also the sample size necessary if I use three continuous predictors.
0
votes
0answers
381 views

Sample size for logistic regression. How to determine the number need for positive and negative cases? [duplicate]

I would like to apply logistic regression for my research. And before that, I want to calculate the minimum number of sample size, positive cases, and negative cases. http://www.medcalc.org/manual/...
1
vote
0answers
159 views

Why exactly is a sample of size 142 too small for 11 variables? [duplicate]

In a (logistic?) regression paper related to credit scoring and involving psychometric data and credit scoring, there are 11 predictor variables used to estimate credit score. The sample size is 142. ...
0
votes
1answer
122 views

What is the minimum number of “cases” for minority class to perform logistic regression? [duplicate]

I have 6 out of 167 cases of cancer in the dependent variable. I would evaluate if three independent variables predicted the cancer. Are 6 cases enough? Is there a rule to determine this? Is there ...
180
votes
9answers
178k views

How to deal with perfect separation in logistic regression?

If you have a variable which perfectly separates zeroes and ones in target variable, R will yield the following "perfect or quasi perfect separation" warning message: ...
93
votes
3answers
87k views

Does an unbalanced sample matter when doing logistic regression?

Okay, so I think I have a decent enough sample, taking into account the 20:1 rule of thumb: a fairly large sample (N=374) for a total of 7 candidate predictor variables. My problem is the following: ...
9
votes
4answers
27k views

Minimum number of observations for logistic regression?

I'm running a binary logistic regressions with 3 numerical variables. I'm suppressing the intercept in my models as the probability should be zero if all input variables are zero. What's minimal ...
5
votes
3answers
9k views

Multiple logistic regression power analysis

I have a logistic regression model and output an $R^2$ value. I then go and add another predictor variable to fit a second model. I can output a new $R^2$ value associated with the second model. When ...
6
votes
1answer
5k views

Power calculations, logistic regression with continuous exposure--cohort [duplicate]

I'm trying to estimate power in a logistic regression with a continuous exposure in a cohort study (ie, the ratio of the sampling probabilities is 1). I have population cumulative incidence (...
1
vote
1answer
3k views

Clarification on the rule of 10 for logistic regression

Been brushing up on my logistic regression and I've seen a couple of things about the one in ten rule. To illustrate my current understanding (or lack thereof) lets consider a case with only two ...
2
votes
2answers
1k views

Power analysis for a factorial logistic regression without estimated proportions for each factor

If we have a balanced factorial designed experiment where each variable is taken in 2 levels (+1,-1) and we don't have estimates of each proportion for each factor level combination like we did in ...

15 30 50 per page