# Questions tagged [logistic]

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

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### probability of interest [closed]

The model that I created in R is: fit <- lm(hired ~ educ + exper + sex, data=data) what I am unsure of is how to fit to model to predict probability of interest where p = pr(hiring = 1). Edit:...
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### What type of regression model do I use?

$y = \mathbf{X} \beta$ + $\epsilon$ + $m$ Where y, $\epsilon$, and $m$ are $n \times 1$ column vectors, $\beta$ is $p \times 1$ and $\mathbf{X}$ is $n \times p$. $y$ is a noisy time-series signal ...
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### Interactions make terms significant in regression when they should not be

I am writing code to prepare for running a logistic regression on real data. I have sample data for all my IVs but not for the outcome variable. There are many strong dependencies among the IVs but I ...
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### Algorithm convergence with logistic classifier

I am doing a college classification project, in which I am required to classify some handwritten digits. Assume that my input is a N*D where D is the number of features in each input sample and I need ...
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### Confidence interval for proportions

I have some data like this: id pop var 1 593 51 2 592 31 3 346 20 4 1214 70 5 1063 66 6 1370 71 each ...
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### Logistic Regression model keeps kicking out 1 dummy

I have a dataset in which each row belongs to one of 8 categories. I'm running a logistic regrssion on it using R. I created dummy variables for each of these categories. In my logistic regression ...
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### logistic regression always yielding increasing f'n when should sometimes be decreasing (using R)

I'm modeling a set of outcome data the depends on two parameters: time, T -100 < A < 100 I've done logistic regression using R with the command: ...
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### Sensible to include ratio as a variable in logistic regression?

I'm creating a generalised linear regression using a binomial link function for two variables A and B. From looking at the data it appears that A/B may have discriminatory effect. Is it sensible to ...
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### Logistic regression: big difference in predicted values and highly significant, but poor goodness of fit

I have a logistic regression model with a dichotomous response variable and predictors coded from $1$ to $10$ and from $0$ to $18$. When I fit the model, I get these results: ...
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### poisson vs logistic regression

I have a cohort of patients with different length of follow-up. So far I´m disregarding the time aspect and just need to model a binary outcome-disease/no disease. I usually do logistic regression in ...
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### Whether to use linear regression or not

Effects of growth hormone (GH) replacement with recombinant human GH on bone and mineral metabolism were studied in 36 GH-deficient children. Several outcomes, including serum ionized calcium levels, ...
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### When the response variable is a proportion (r/n) in proc logistic, how to express the model in terms of $\pi, \alpha, \beta$?

A (SAS documentation file) (page 1906) on "The LOGISTIC Procedure" gives the following procedure- proc logistic; model r/n=x1 x2; run; Here, n represents the ...
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### Adding not chosen alternatives as data to logistic regression model

I am interested in predicting shopping behaviour in a shopping center. I have a database with the chosen alternatives (shop) and variables describing that alternative (like type and size) and the ...
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### Choosing between logistic regression and Mann Whitney/t-tests

I have a dichotomous variable $A$, which does not have an a priori determined proportion of 0's and 1's, and a continuous variable $b$. In scenario 1, I decide to designate $A$ as the independent ...
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### Shifted intercepts in logistic regression

I have a question about the effects of shifting the intercept in a logistic fit on the mean of a particular transformation of the scores. Here is the notation I will be using for the question. The ...
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### "Wrong Sign" On Regression Coefficients - Hierarchical Multiple Linear Regression

I am analyzing my data on the relationship between spirituality and negative emotional states (depression, anxiety, and stress) using a hierarchical multiple linear regression. Everything seemed to be ...
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### Why am I getting a zero parameter estimate and SE for one of my variables in a logistic regression?

I am doing a binary logit analysis, in which I'm trying to fit a model to my data to explain why some towns adopt open space subdivision ordinances (OP), using a handful of discrete and continuous ...
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### How to calculate 95% CI for OR for a different reference category without running the SAS logistics again?

My question is about calculation of confidence interval (CI) for odds ratio (OR) from a SAS output of a logistic regression model for a different reference category without running the SAS program ...
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### Which model to use with repeated measures data that contains multiple binary dependent variables

What model should I use??? I have daily repeated measures data. It has multiple dependent presence absence variables, (of which, I have collapsed into a CA with continuous variables of CA1 & CA2....
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### Predicting ordered logit in R

I'm trying to do an ordered logit regression. I'm running the model like so (just a dumb little model estimating number of firms in a market from income and population measures). My question is ...
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### Is there a better alternative to a logit / probit regression when all dependent variables are dichotomous?

I'm working on a clinical trial dataset with binary response. All independent variables are also binary. My first impulse was to simply run a standard logit / probit regression and be done with it. ...
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### Polynomial kernel in logistic regression?

So I have put together a nice logistic regression program that works quite well. Now, I have used two dimensions to test it and see how it works, and guided by some online tutorials, have increased ...
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### What is the difference between a "link function" and a "canonical link function" for GLM

What's the difference between terms 'link function' and 'canonical link function'? Also, are there any (theoretical) advantages of using one over the other? For example, a binary response variable ...
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### Can I interpret the inclusion of a quadratic term in logistic regression as indicating a turning point?

In a Logistic Regression with linear and quadratic terms only, if I have a linear coefficient $\beta_1$ and quadratic coefficient $\beta_2$, can I say that that there is turning point of the ...
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### How to diagnose multicollinearity using the output of vif function in R?

I am running a logistic regression in R and am attempting to determine if multicollinearity is a problem with my model. When I run vif() on my final model, I get <...
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### How to encode factors as dummy variables when using stepPlr?

When using the step.plr() function in the stepPlr package, if my predictors are factors, do I need to encode my predictors as dummy variables manually before ...
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### Logistic regression on a dataset with duplicated records

I have a large data set with multiple records per phone number. Each record has two variables - the number of past attempts in the past 60 days (number of times it was called) which range from 0 to 30 ...
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### Logistic growth inflection point

I have a logistic growth curve as follows: $y = \frac{1}{(1 + ae^{-bx})}$, where x is the independent measure (x-axis) and a and b are paramaters. The inflection point of this equation is when y = 0....
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### How to determine the best relationship (linear, log, etc.) between input predictor variable(s) and output variable for multiple linear regression?

I am trying to determine the most accurate relationship between two variables (each predictor versus the output eventually). I want to know if the relationship is linear, or log-linear, or log-log, or ...
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### Regression with repeated measures in Matlab

Is there a way to perform multiple logistic regression on repeated measures data using Matlab? I have a data set containing a daily measurement recorded from 20 participants for 60 days. I am ...
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### Reporting contrasts between binary probability parameters in Bayesian data analysis - odds ratios or difference in probability?

In a bayesian data analysis, if one is modeling differences in binomial/bernoulli probability parameter differences between populations, is it still standard to report the difference in the binary ...
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### Using multinomial regression's coefficients to derive predicted outcomes in C#

I am attempting to use C# (and the alglib library) to calculate the predicted probability that an outcome ends up in one of five classes. I have managed to calculate parameter estimates (i.e. slope ...
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### Does learning rate have additional meaning in logistic regression?

I try to implement logistic regression with auto-correcting learning rate and I am puzzled by the outcome. At some point the cost of the function gets bigger than previously (to focus on some numbers ...
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### How do you get lmFuncs functions of the rfe function in caret to do a logistic regression?

I've been experimenting with the rfe function in the caret package to do logistic regression with feature selection. I used the <...
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