Questions tagged [logistic]

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

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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 ...
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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 ...
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1answer
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 ...
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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 ...
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1answer
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 ...
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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. ...
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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 ...
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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 ...
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1answer
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))) ...
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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=...
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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 ...
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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 ...
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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 ...
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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 ...
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2answers
238 views

Interpreting a generalised linear mixed model with binomial data

I have a generalised linear mixed model with binomial response data, the model: ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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4answers
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 ...
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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3answers
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 ...
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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 ...
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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.
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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 ...
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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 ...
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1answer
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 ...
1
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1answer
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. ...
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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 ...
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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 ...
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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?
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1answer
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 ...
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1answer
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'...
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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 ...
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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 ?
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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 ...
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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 ...
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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 ...
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1answer
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 ...
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1answer
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 ...
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1answer
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 ...
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30 views

… This is random, right? [closed]

The X and Y axis are predictor variables, and the response is 1 (the + sign) or 0 (the circles). I shouldn't explore this further, right? There's no way to predict for 1's?
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1answer
49 views

What's the interpretation of the ratio of the odds ratio between the experimental and the control arm?

Table 1 of this article show the associations between the outcome and variables, the authors presented the OR_ctr in control arm and ...