# Questions tagged [regression]

Techniques for analyzing the relationship between one (or more) "dependent" variables and "independent" variables.

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### What are the differences between stochastic and fixed regressors in linear regression model?

If we have stochastic regressors, we are drawing random pairs $(y_i,\vec{x}_i)$ for a bunch of $i$, the so-called random sample, from a fixed but unknown probabilistic distribution $(y,\vec{x})$. ...
22 views

### Understanding the causes and implication of heteroskedasticity

I’m trying to heteroskedasticity and how, even if we don’t have MLR 5 assumption (heteroskedasticity), we can still have unbiased estimates. I was thinking: a very intuitive cause of a growing ...
18k views

### What is a contrast matrix?

What exactly is contrast matrix (a term, pertaining to an analysis with categorical predictors) and how exactly is contrast matrix specified? I.e. what are columns, what are rows, what are the ...
5 views

### Does the model selection in this study make sense?

I was introduced to the following study. It seems to me that they are comparing three groups with a lot of predictors. If this was my study I would have just ran a mixed model or an ANOVA to compare ...
6 views

### In case of “No breakpoint estimated”, should I use only linear regression instead of time segmented analysis in R?

I am trying to do 2-time segmented analysis using the package segmented in R but I am encountering errors that I tried to figure ...
8 views

### Method of Data-Analysis

For my research I'm examining whether applying a certain promotional intervention improves the amount of misshapen products bought. The study contains of two parts. In part 1 Scanner data from ...
423 views

### Beta coefficient (Partial Least Squares)

Kindly advise if the value of beta is obtained in the results when a Regression analysis, Pearson Correlation or Partial Correlation is conducted. I understand that beta reveals the strength of a ...
10 views

### What are the reasons why a regresion prediction with a threshold cannot be used as classification?

For example, lets assume there are two models: A logistic regression for whether or not it will rain the next day A linear regression for the amount of rainfall tomorrow What are the reason why and ...
5 views

### Valid alternative to Box Tidwell method for Linear Regression [duplicate]

I am building a Logistic Regression model (in sklearn) and want to verify that the assumption regarding the linearity between X and the logit function is correct. I am using Python so am looking for ...
9 views

### Valid alternative to Box Tidwell method for Linear Regression [duplicate]

I am building a Logistic Regression model (in sklearn) and want to verify that the assumption regarding the linearity between X and the logit function is correct. I am using Python so am looking for ...
2k views

### Multilevel logistic regression with a random slope(s)

I would like to specify a two-level logistic regression model with random intercept and random slope. Dependent variable: hospitalization (1) or no-hospitalization (0). Independent variables: age, ...
202 views

### Question about sliding differences contrast coding rationale

I've been reading up on sliding differences coding (forward differences coding, on the ucla page: http://www.ats.ucla.edu/stat/r/library/contrast_coding.htm). Here is the contrast matrix recreated ...
16 views

### Calculate probability of outcome of a medical procedure

I have data on medical procedures completed at hospitals in major U.S hospitals. Each medical procedure is assigned a code, for example: Kidney Transplant is X6571. I define the success criteria and ...
155 views

### Reading a pressure gauge with a CNN

Using standard Computer Vision pipelines to read pressure gauges is well established, and not overly accurate or generalizable: For various reasons, I would like to use a CNN to do this. Since the ...
9 views

### Question on Cross Validation Assessment on Training/Validation/Test Sets

I want to make sure I am grasping Cross Validation (k-fold or single validation set) correctly in a high-level sense. The idea is to first split the data into 3 sets, Train/Validation/Test. I train ...
5 views

### orthogonal projection in an algorithmic procedure for LARS

To my best understanding, the steps for Least Angle Regression are as follows: ...
15 views