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# Questions tagged [centering]

Centering involves subtracting the overall sample mean score from the original score; standardizing does the same followed by dividing by the overall sample standard deviation.

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182 views

### How can centering predictor variables reduce correlation between them?

In Statistical Rethinking by Richard McElreath on pg. 320 he states “centering predictors can aid in inference, by reducing correlations among parameters”. For a linear equation with an interaction ...
294 views

### categorical predictors in partial least squares

I am interested in running a partial least squares analysis using PROC PLS in SAS 9.4. I understand that, by default, the predictors and response variables in PLS are centered to a mean 0 and scaled ...
60 views

### Mean centering and normalization along every dimension or over whole dataset

I'm working a side project which involves using a pre-trained CNN and I came across a piece of code that made me question some of my recently gained knowledge around mean centering and normalization. ...
89 views

### centering in mixed effect logistic regression

I am working with a mixed-effect logistic regression with two independents (a and b, dummy coded 0 or 1), which have a fixed effect for a, b and the paired interaction as well as a random effect of M ...
24 views

### Is it wrong to standardise a variable and then centre it for use in multiple regression? [duplicate]

Is it wrong to standardise a variable (e.g. polygenic risk score) and then centre it for use in multiple regression?
113 views

### Why are the normal equations $X_c(X_c'X_c)^{-1}X_c^Ty$ for centered OLS?

I'm working through a centered OLS problem. If $X$ has an intercept column, $y = X\beta + \epsilon \Rightarrow y = X_c\beta_c + \gamma_0 + \epsilon$ where $X_c$ is the centered design matrix. My ...
713 views

### Multicollinearity and centering [duplicate]

I read nearly all topics about collinearity but still have some questions... I know: multicollinearity is a problem because if two predictors measure approximately the same it is nearly impossible to ...
149 views

### Multinomial logistic regression - centering and using dummy coding?

I have two IV's: cognitive ability test scores (a continuous variable), and task difficulty levels (3 levels: easy, medium, difficult) I want to predict a categorical outcome with 3 types of behavior (...
20 views

### Rank of N x D vs D x N matrices

If $X$ is a random $N \times D$ matrix where $N > D$, then why is the rank of X - mean(X, 1) $D$ while the rank of ...
91 views

### choice of mean for mean centering

I am doing statistical analysis of empirical data using a a generalized ordered regression model. I would like to test for interaction terms. I have a 3-level categorical IV (coded as 2 dummy ...
94 views

### Analyses when IVs highly correlated - is there anything I can do?

I'm doing some analyses in which I have 1 continuous independent variable (IV) and 1 dichotomous independent variable (IV2) that's a demographic covariate. I'm now realizing that they are extremely ...
1k views

### Why does my centered variable not have zero mean?

It is well established that centering a variable, i.e. subtracting the mean of that variable from every value produces a variable with zero mean. For example: ...
55 views

### Center data in quantile regression?

I have 25 years of nest initiation dates, I used quantile regression to look for changes in the distribution over time, as well as to look in detail to early and late breeders. My model would be ...
409 views

### Should I use mean centering or not?

I am using a logistic regression model. I want to see interaction effect of a continuous Independent variable on the relationship of another binary independent variable and the dependent variable(DV ...
26 views

### How to represent multiple data by single value

I have three inputs x1,x2,x3 and to each single input there are three outputs y1, y2, y3. (1) x1 --y1, y2, y3 (2) x2 --y1, y2, y3 (3) x3 --y1, y2, y3 The Whole whole set has to be represented by ...
173 views

### Representative terms per clusters based on tf-idf

I have a result of text clustering based on TF-IDF. I have $k$ clusters. How can I get the representative terms for each cluster $I=1,\dots,k$ using the TF-IDF matrix? Is there any standard way to do ...
834 views

### Decision to center fixed effects in GLMMs in lme4

I'm constructing a GLMM using lme4 in R, and am unsure as to when it is and isn't best practice to center fixed effects. For this model (with logit link), for example: ...
41 views

### Should I center the data when performing Laplacian Eigenmap or any other manifold learning?

Suppose I have a high dimensional non-stationary non-linear time series, then is it advisable to center the data on the mean when performing laplacian eigenmap? I've heard somewhere that when ...
40 views

### Why does the standard error of the intercept change when we shift the axis, say by centering? [duplicate]

I was trying to understand how the calculations are done behind lm() function in R using mtcars dataset. I understand that ...
55 views

### Variable centering on the sampling distribution of the coefficient estimates

I think the question may be silly but I'm trying to learn statistics and R and this is really hard for me because I'm a newbie of both. I have this exercise to do. Carry out a simulation ...
47 views

### What should I to do to cope with multicollinearity problem?

I employed a multiple regression model by applying a backwards selection method of model selection to examine the influence of three explanatory variables their interactions in determining oxygen ...
60 views

### Is there a rule of thumb to choose a specific standardization method for regression?

I have been reading some resources and various techniques have been used to standardize the predictors in a regression model. Below, the first two are common approaches as far as I understand. The ...
194 views

### Formulate a z-test into a general linear model

I've heard it said that most statistical tests can be reformulated within the GLM framework. I can see how that can be done with a two-sample t-test (dummy code group membership and interpret the ...
394 views

### Scores are still correlated after PCA

I have 22 variables with more than 6000 observations. They are highly correlated. I know these data would work as great explanatory variables to a dichotomous event (present absent). Therefore, I ...
226 views

### Centering and assumptions of 3-level multilevel model

I am struggling with formulating a multilevel model for my analysis and would really appreciate if you could give me some insight. This is a 3-level model where the response (Y), exposure (X), and ...
814 views

### Standard deviation non centered (normal) data

I'd like to get a prediction interval (or a good measure of dispersion) of my data but it seems like standard deviation is not the right way to do it because my data is not centered (or not normally ...
1k views

### Mean centering or not in the context of Partial Least Squares

In my current project, I'm using PLS regression on infrared spectra (FTIR). For this I'm using R and the pls function from the plsr package. ...
9k views

### Does random forest need input variables to be scaled or centered?

My input variables have different dimensions. Some variables are decimal while some are hundreds. Is it essential to center (subtract mean) or scale (divide by standard deviation) these input ...