Questions tagged [standardization]

Usually refers to "z-standardization" which is shifting and rescaling data to assure they have zero mean and unit variance. Other "standardizations" are possible, too.

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32 views

Standardise components of an additive model output

I've got a sales forecasting model using the fbprophet library. The model is additive: calculates a base trend and then adds ...
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65 views

Using standardization methods to exclude erroneous outlier values

As my data has a lot of outliers, using mean to standardize data doesn't seem to be optimal. I'm experimenting with using median to classify outliers and stumbled upon robStandardize function from ...
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32 views

Standardizing data produces negative values

I am working on a basic house price prediction problem with traditional ML algorithms, not NN since the size of data is small comparing to the number of features. The issue I am having is that many ...
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51 views

Small Sample Size and NOT normally distributed

Say $n_1=4$ and $n_2 = 5$. If I want to compare the mean, should I: Standardize the data (i.e., using the scale() function in R), then perform t-test. This is because t-test required the data to be ...
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When comparing the ACT and SAT by converting both measurements into z scores, why is it that the person with the smaller z score has the better test?

I was reading this article: https://medium.com/omarelgabrys-blog/statistics-probability-probability-distribution-35818d301cf4#fbef and, in one section of the article, the author compares two students....
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1answer
30 views

RMSE with and without standardizing the output variable

I have a time series data that I would like to be able to forecast. I was trying to standardize the data as my columns are all of different ranges. I have standardized the input variables, but was ...
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2answers
27 views

Transformed continuous variable Z-Score to Percentile

I had a non-normal distribution of my variable of interest which required log10-transformation to reduce outliers. This was then standardized, to a mean of 0 and sd of 1 (z-score?). I now want to ...
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12 views

De-standardizing covariance matrices after applying PCA?

If I decide to use PCA to estimate a high-dimensional asset portfolio covariance matrix using reduced dimensions, I can use the following procedure to transform the low-dimensional matrix back to the ...
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1answer
51 views

Why standardization of design matrix $X$ with factor $\frac{1}{n}$ instead of $\frac{1}{n-1}$ in lasso/glmnet?

I'm a little bit puzzled by the default standardization of the lasso/elastic net/ridge regression algorithms implemented in the (great!) glmnet package. In most other applications, people would ...
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18 views

What type of Normalisation technique is best for image data before applying any CNN deep learning model on type of it? [duplicate]

How to decide upon the normalisation that need to be used for image classification or cv problems , Is there any standard on what to choose when in particularly with Image data ?
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Feature Scaling/Standardization or Change Point Score?

I've different data sets that have the feature Volume. This feature represents the absolute number of events. Each observation represents a period (a fixed period such as 15 minutes). You can imagine ...
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1answer
31 views

CFA: scaling of measured variables/indicators

I'm running a latent variable analysis with: 166 observations 21 continuous variables using the R package lavaan A simple run of ...
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1answer
66 views

Two dumb questions about standardization and overfitting [closed]

The following two questions may seem to be dumb, but I could not figure out reasons to convince myself. Question 1 Why neural networks (or more generally, any machine learning models) tend to ...
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Effect of learning rate (and standardization) on NN with ReLu layers [duplicate]

I'm trying to understand the effect of the learning rate on a 10x10x10x10x4 sequential NN. Where each hidden layer is ReLu and the output layer being Softmax. I know the theory: low rate -> slow ...
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31 views

Significance for regression or standardized regression coef

I'm calculating multiple regression with R and trying to decide which predictors to keep and which to drop. I realized that when I use the lm.beta function I'm not ...
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27 views

Why would you subtract the mean of your variance from your variance? [duplicate]

i recently stumbled over the following codeline: variancedm<-variance-mean(variance) Is this a common way to normalize/standardize variance ? Why would you ...
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2answers
61 views

Do we need to standardize when our data is univariate?

In this question: What algorithms need feature scaling, beside from SVM? it is said that we need to standardize so that all features are weighted equally. But what if we only have as features: time ...
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26 views

Interpretation of a regression coefficient

How should I interpret my regression result as my independent variable is in log format and my dependent variable is standardized to a mean of zero and standard deviation of one. More specifically, is ...
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61 views

Should you standardize your variables before or after removing outliers?

Barring the question of how to operationalize outliers, or the utility of doing so, and assuming dependent variables and independent variables are all scaled in the main regression specification (...
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19 views

transform different measures for correlation analysis

I inherited data from different companies which used different tools to measure customer preference. Now I would like to correlate customer preference with another variable. The problem is that ...
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21 views

Which Comes First: Standardization or Transformation?

I have a data frame that contains a few variables where the skew is larger than 1. Also most of the variables have vastly different scales. I am looking to scale the data using R's scale() function (...
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53 views

Help needed to Interpret ln(y) = a +b (Standardized X)

I am analysing server data and I have a scenario where I need to get the % by which Y is changed because of a unit change in X: EDIT: I am doing a Linear Regression in Python (and its other forms ...
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39 views

Difference between standardizing variables and using Mahalanobis distance

I am wondering how and/or why the Mahalanobis distance is different from using the Euclidean distance on standardized variables?
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In linear regression, what would it do to center the label?

In this question linked below, it was addressed why we would center the features in linear regression. When conducting multiple regression, when should you center your predictor variables & when ...
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Standardizing dummy variable in multiple linear regression?

I have a multiple linear regression model with several independent variables in different units. Because some of my data is negative, I am unable to take the log and therefore am standardizing the ...
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How to (and if) transform and standardize two types of data (count proportions & low-value inflated latencies) for a MRIM model

I am looking to analyse a variety of traits in a Multivariate random intercept model (MRIM) with the help of the MCMCglmm package in R. All traits are measured on different scales so I wish to ...
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38 views

Standardizing variables in lavaan (cross-lagged panel model)

I am running cross-lagged panel models with lavaan (3 time points, with and without random intercepts, as shown here https://jflournoy.github.io/2017/10/20/riclpm-lavaan-demo/ ). I noticed that when I ...
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1answer
24 views

Normalizing data before or after extracting time domain features

I have 100 time series (with 200 instances each) datasets each corresponding to a particular activity. I want to perform supervised classification for the activity. I want to use time domain (time-...
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22 views

Interactions: mean centering, standardizing and standardized coefficients (betas)

I mean-center my independent and moderator variable before calculating the interaction term to avoid multicollinearity. In my regression output table, I subsequently report the standardized ...
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23 views

Comparing z-scores, one variable pre-/post test

I am working on an assignment where I am going to compare a group of students test scores measured in a pre-test with the same group of students test scores measured in a post test. Due to the way ...
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37 views

Can I standardize/normalize proportion data using z-scores

I am trying to determine the temporal repeatability (repeatability over time) by conducting the same test on individuals twice. I then try to compare the results from these tests. I have a variety of ...
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13 views

Data normalization in ridge regression when there is no intercept

I would like to have a linear model without an intercept and also without the target being centered. How should my data then be normalized when using ridge regression? If I standardized the variables ...
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22 views

High Correlation after Standardization

I was working on a time series data, where there's a very low relationship between the variables(0.1 to -0.1). After applying standardization to each of the features, half of the it starts to bear ...
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34 views

How to interpret impulse response analysis in VAR when using standardized variables?

How to interpret impulse response analysis when using standardized variables (ie., subtracting the mean and divide by standard deviation) in vector autoregression analysis? The reason why I ...
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1answer
62 views

Quadratic term of standardized predictor in logistic regression

A random intercept logistic regression is performed to assess the association between $Y$: Disease (Yes/No) and Standardized Predictor($X_1$) adjusting for control variables ($X_2$, $X_3$) based on ...
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1answer
49 views

Why does AIC model rank order change in lme models with standardization of predictor variables?

I can't figure this out. The AIC/AICc rank of my mixed effect models are different whether or not I standardize my predictor values using rescale. Note, I'm not concerned that AICc is changing, as ...
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25 views

Do I scale panel data as a whole or do I group it first?

I am running a panel regression estimating the effect of a change in employee satisfaction for a given company on the stock price(adjusted by Fama-French). I do have a panel with 50 companies and 43 ...
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17 views

Confused about z-score image normalization output

I am trying to normalize my input data for a convolutional network, I applied the z-score normalization technique to my image dataset as follows: Formula: (image - mean(image)) / std(image) ...
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12 views

Chance&ceiling performance when using non-standardised hit&false-alarm rates

What is lost/missed out on if defining d', the sensitivity index from Signal Detection Theory, based on non-standardised rates? For example, Patel et al. 2008, for a task where normal and anomalous ...
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1answer
107 views

Interpretation of standardized (z-score rescaled) linear model coefficients

I have analyzed some data on vegetation change as a function of change in soil parameters. I compared a dataset from 2001 with a dataset from 2018 (fully balanced). To investigate the change in ...
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1answer
39 views

Standardizing versus percentile rank with survey data

I am currently working with survey data, collected across different locations, but with slightly different units of measurement. For example, on questions such as "What is your level of education", ...
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63 views

What is the proper way to standardize non-stationary data?

I have a 19-year time series of satellite imagery (spaced irregularly temporally). The mean and standard deviation of the dataset changes over the 19 years. I get multiple variables from each image; ...
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12 views

Variable selection with standardised variables

Recently I performed a lasso regression on a set of 1000 standardised time series variables to select variables to use in a linear regression model. I used the non-standardised original form of the ...
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1answer
40 views

How to standardize data with low variance?

I have quarterly data of federal fund rate (test set), e.g.: ...
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30 views

Standardization based on subsamples

I need to analyze data on the cognitive performance in a sample of participants divided into clinical (36 participants) and non-clinical groups (~100 participants). What would be the correct ...
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3answers
162 views

Standardised mean absolute error (SMAE) and how to calculate it?

I am using the mean absolute error mean(abs(obs - pred)) as one of the measures assessing the fit of my model. I would also like to have a standardised measure ...
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87 views

Z score standardisation vs min-max scaling for feature selection

I am applying l1 norm on the input weights of a single layer MLP. I wanted to know if I should standardize or min-max scale ([0 1] feature scaling) my input data?
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Construct least-squares ultrametric (hierarchical clustering) fits to doubly-standardized “flow” tables and compare to single-linkage-type fits

Figure 1 of the paper, "Hierarchical Migration Regions of France" (IEEE Transactions on Systems, Man and Cybernetics, 4 (1976) 321-324) (https://www.researchgate.net/publication/...
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1answer
47 views

Standardization of Data

I have a dataset which consists of Sales for Product1 and Product2. It also tells if the <...
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Direct standardisation with missing values on ages

I am aiming to perform a direct standardisation to calculate the prevalence rate of a certain condition in an area. What I did was to merge different routinely collected health data to be able to ...