# Questions tagged [logistic]

Refers generally to statistical procedures that utilize the logistic function, most commonly various forms of logistic regression

6,057 questions
Filter by
Sorted by
Tagged with
15 views

### Understanidng population-averaged vs unit-level (logistic)

As a statistics beginner, I still have trouble understanding the true difference between population-averaged (xtgee) vs. unit-level (xtlogit) predictions. Conceptually, I have constructed myself the ...
15 views

### What do the different correlation structures mean with gee?

Statistics beginner here, trying to self-study in order to perform regression on a dataset that I have. Currently, I am trying to understand what the different correlation structures are and imply ...
19 views

### How to improve Recall and Precision?

I am working on a big data set which has 25 features with 237862 number of rows. I am trying to predict return . 1 is for return and 0 for no return. My data set has 12% of data which returned. So ...
29 views

### Calibration-in-the-small and logistic regression

It is well agreed (for example this discussion ) that Logistic Regression guarantees that model will produce well calibrated in the large (mean) predictions. Does Logistic Regression guarantees ...
48 views

### Why is odds ratio used when interpreting logistic regression?

I am fairly certain when interpreting logistic regression output, the odds ratio should be used instead of the estimated coefficients; however, I am unable to figure out why this is the case. So my ...
8 views

### Estimating a learning curve without gold standard

Consider the outcome of a diagnostic tool in medicine: each patient has either the disease or is disease-free (0/1). Now, let's further assume that it is not possible to have a false-positive, i.e. ...
23 views

### Sample Size for Logistic Regression FOR DUMMIES!

I need to know the minimum sample size for a logistic regression analysis. I have 2 continuous predictor variables. I've read some similar questions here, but the answers are way over my head. I ...
14 views

### Beta regression or logistic regression with an offset term?

I have a dependent variable (DV) that is a proportion that is bounded by [0,1). Initially I was considering using a beta regression to model the relationship between this proportion and two other ...
10 views

### Converting an effect on complementary-log scale to odds ratio

I'm trying to figure out how "an effect of treatment (beta) = 0.5 on complementary log scale" translate into an odds ratio (with baseline risk = 0.35)... I found the clog-log h(t) = log(-log(1-h(t))) ...
23 views

### Hypothesis testing of logistic regression coefficient [duplicate]

We define there is a deterministic model between X and Y(which takes the value of either 0 or 1). However, due to some unobservable variables were left out, our equation becomes Y=βX+ ϵ. Furthur, P(Y=...
24 views

### the difference between GLM and fisher's exact test

recently I want to compare the enrichment or overlapping between 2 lists. I found some paper use fisher's exact test, or other papers use GLM(logistic regression). Does anyone know what the ...
21 views

### Pseudo $R^2$ low from val.prob calculation

I have just created a logistic model, and now I want to validate it. Therefore I am using the val.prob function from the rms ...
6 views

### Effect of Bimodal distibution and mitigation while performing Classification

I am trying to solve a classification problem where one of my numerical attributes age is BiModal in nature. Will it cause any ...
9 views

### Accounting for Pre-Period Bias in AB Testing with Logistic Regression

Question Context This is more of a conceptual question although a concrete example is provided for clarity. My company uses AB testing to understand the impact of various email campaigns on customer ...
238 views

### Interpreting a generalised linear mixed model with binomial data

I have a generalised linear mixed model with binomial response data, the model: ...
20 views

### What to report for logistic regression? [closed]

First of all, I am by no means a statistician by education (only physics), but I try to learn obviously. Anyways, let’s say I have developed a predictive logistic-regression model. I now need to ...
32 views

### Why is my meta analysis OR and 95% CI less precise than my study results?

I am trying to perform a simple weighted average meta analysis of 2 odds ratios from 2 studies (I will be adding more studies when I get the results). However, when I meta analyse using the METAFOR ...
32 views

### Is it possible that I have a precise logistic regression model, while coefficients are not significant?

I am working on a ordered logistic regression model. My predicted variable is multinomial and has several ordered levels. After several experiments with different types of models with different link ...
23 views

### The parameter in the population logistic regression line and its statistical inference [closed]

Under the assumption of the distribution of error and also the form that X takes to affect Y, we get this probability function: P = exp(β'x)/ (1 + exp(β'x)) Therefore, does it mean that we are ...
28 views

### How to calculate the observed absolute treatment effect?

I'm reading this article. The authors indicated that for a random sample of 12 characteristics and 3600 patients affected in tow arms (control and treatment arm), they fitted some treatment effect ...
869 views

### Dichotomizing continuous variables at their optimal cut-off for clinical interpretation

In medical context, when presenting results from a binary outcome with a continuous predictor, the OR (odds ratio) can be difficult to interpret. Example: A doctor does a study in which he wants to ...
21 views

### What does it mean if a regression model is not significant, but individual variables are? [duplicate]

With a logistic regression model of 3 independent variables, one of the variables is significant while the other two are not. The significant variable is my variable of interest while the other two ...
37 views

### Assumption of error of logistic regression [duplicate]

I know there are debates about whether the error exists and its distribution in the case of logistic regression. Suppose we assume that the error term follows the logistic distribution. Are we ...
12 views

### How is standard error of regression coefficient calculated (quadratic and logit)?

I was wondering what formula is used to calculate the standard error of quadratic and logit regression coefficients. I don't have much knowledge on statistics and I have had trouble finding sources ...
25 views

### Proper procedure for logit regression

The data I've been given has a mass of two level factor variables, roughly 10. However, all of these variables are mutually exclusive. The online form is recording whether you checked a box or not, ...
9 views

### Manual calculation of logit regression [duplicate]

I have been working on Logit regression and I don't understand how to find coefficients by hand. I have seen that its possible to do it using maximum likelihood but I don't have much background in ...
25 views

### Should I run several Lasso regressions to answer my question? [closed]

I've got about 10 variables that I am interested in knowing whether predict my outcome y (binary). I'd also know if these variables should be controlled for in between each other. I'm thinking maybe ...
13 views

### Categorical variable and Logistic regression model

I am trying to run a logit model with different types of independent variables like dummy, continuous and categorical variables. But I am facing problems in the categorical variables. Here, my ...
406 views

### Variable selection in logistic regression model

I'm working on a logistic regression model, I have 417 independent variables to try, but running a model with all of them is too much (for Rstudio), what would be a good criteria to discard some ...
8 views

### Logistic regression: McFadden does not change after interaction term is added. But Waldtest shows differecne in model fits

I have tested two models (one with interaction, the other without). The McFadden test show just small improvement in model fits (.432 to .439). When I run Waldtest between the model, it shows that ...
11 views

### P value significance in R [duplicate]

I understand that this p value: < 2e-16 is significant But is this p value: 1.4e-05 significant? I'm not sure how you can tell / what the 'e' means. Any help appreciated, thanks.
19 views

### how to choose performance metrics when forward selecting in logistic regression?

I am new to statistics. I am performing a multi-class logistic regression and I want to select the important features. So I am implementing a forward selection. So, first I normalised the data and ...
31 views

### Can you use multiple reference groups in a single logistic regression?

When performing logistic regression for a binary categorical variable (i.e. 'gender', being Male or Female in this simple ...
26 views

### How to specify a risk model?

I'm reading this article. The authors indicated that for a random sample of 12 characteristics and 3600 patients affected in two arms (control and treatment arm), they fitted a risk model consisting ...
24 views

### Computation of the intercept in logistic regression model

I'm trying to understand the way the odds of the reference groups are computed. Let's consider an example from this paper. Data can be summarised in the table: The reference group is Older and New. ...
18 views

### Would a multiple regression controlling for one variable increase the validity of my study?

I have a study in which the problem is a very low power (low amount of people in the outcome variable). I found during a previous question I asked that we should probably not use multiple regression ...
31 views

### Classification on rare events (~%3) and only categorical variables

I need to build a model based on about 10 independent variables, all categorical (only two of which are potentially ordinal), to predict a dichotomous output ('1': 3%; '0': 97%). To overcome the ...
25 views

### How do I interpret that table? What is that table saying and is it related to the text below the table? [duplicate]

How do I interpret that table? What is that table saying and is it related to the text below the table?
22 views

### How can one define the power of a randomized clinical trial?

The statistical power of a study is a measure of the ability of a randomized clinical trial (RCT) to detect a difference statistically significant of the treatment effect in the treatment arms. How ...
37 views

### Having a problem reading my multiple logistic regression model

I have a logistic regression model that is seemingly significant when regressing individual variables in a univariate regression, but the entire thing falls apart when input into a multiple model. I'...
12 views

### Can I assume data points follow Logistic Distribution with distances from the decision boundary in Logistic Regression?

While I was doing some researches on Logistic Regression, I read a post saying that distances from the decision boundary in Logistic Regression follow Logistic Distribution. I am not sure if the ...
20 views

### How should we preprocess our data before logistic regression? [duplicate]

Is it necessary to normalize continuous variables before logistic regression ? Or rather use min-max transformation ?
33 views

### Logistic regression in R - understanding function outputs

I'm looking to gain more understanding on how to properly perform logistic regression using R. I have a matrix x with 20 features (columns) and 1000 samples (rows) and a response vector y with values ...
13 views

### likelihood ratio test for logistic regression with a complete separation

Can likelihood ratio test be used for logistic regression in the case of complete separation? I understand that individual parameters can go to infinity so Wald's test is not recommended, but does ...
13 views

### Getting extraordinarily large coefficients on otherwise seemingly normal numbers in logistic regression?

I've got a logistic regression for a binary outcome and a continuous predictor that stretches from 0.28 to 0.55. The relationship is U curved in nature so for predictor "p" and dependent "d" I regress ...
20 views

### How can I draw decision boundaries for three different classes in Logistic Regression?

I understand the equation to draw a decision boundary in Logistic Regression with 2 independent variables and 2 different classes but when it comes to 3 different classes with 2 different independent ...
23 views

### How to determine feature effect size distributions in logistic regression across many models?

I have a dataset of 100 measurements each with 20 features. I am randomly pulling 90% of the data, training a l1 penalized logistic regression model and then testing on the remaining 10%. I repeat ...
44 views

### Why and how to match variables using logistic regression?

I have a dataset of ~4.7K records focused on binary classification with 60 features. class 1 is of 1554 records and class 2 is ...