Shifting and rescaling data to assure zero mean and unit variance.

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40 views

Can I use z-scores to compare data measured in different units?

I am trying to compare the accuracy of two different methods of estimating biomass. This data is in the form of percentage cover (and is arcsine transformed). I also have the real biomass values, ...
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37 views

R code for standardized coefficents and model effect size using nlme

I have fit a longitudinal random effects model using nlme and I prefer nlme because I can get p-values. While working with a ...
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2answers
22 views

Comparing within-subject z-scores (survey data)

I have some messy survey data, wherein one group of interest (cut on one self-reported behavior) rated every single attribute (7-point Likert scales) higher than any other group. I think this has ...
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1answer
32 views

Standardizing vs differencing to remove non stationarity

To remove non stationarity in a time series, we can standardize the time series by subtracting the mean and dividing by the standard deviation. We can also keep differencing the time series until the ...
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0answers
9 views

Raw values vs SDS for linear regression?

I have data on age, gender, height, weight and a health variable (call it yvar) which is a continuous variable in the range of 50-150. The age is in the range of 5-15 years (a study of children). I ...
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5 views

Calculate trending of content from multiple sources

I'm not fantastically mathematical so please excuse any mis steps. Let me start with what I'm trying to do: I have news sources, for example: A. Washington Post B. TechCrunch C. Krebs on Security ...
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1answer
25 views

Multiple Regression - Converting Standardized Coefficients to Unstandardized

I recently performed a multiple linear regression using a standardized set of data, and I was wondering if it possible to convert the standardized coefficients from the regression into usable ...
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0answers
38 views

Estimating mortality rates with direct age-standardization

I'm attempting to calculate the mortality rates of AMI (acute myocardial infarction) in patients (cases) with high bloodpressure, between the years 2001 to 2008. For every case I have 2 matched ...
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1answer
33 views

Is there a way to characterize the position of a point in a distribution that takes higher moments into account?

When summarizing a location in a distribution, we can take the mean into account by simply calculating $x-\mu$. We can take the standard deviation into account by calculating a Z score ...
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3answers
41 views

What is a good paper or book to understand standardization and normalization of data with different units of measurement?

I am dealing with data with different units of measurement for NYC neighborhoods and I am trying to build a composite score with it. For example, I have total population by neighborhood, mean income ...
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1answer
24 views

Retrieving the Unstandardised coefficients from a Standardised Regression

Is it possible to retrieve the Unstandardised Regression Coefficients from a Standardised Regression? If so, how is does one do this in order to use the coefficients to make predictions on new data? ...
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49 views

Coefficient value from glmnet

I am running glmnet for the first time and I am getting some weird results. My dataset has n = 139; p = 70 (correlated variables) I am trying to estimate the effect of each variable for both, ...
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36 views

When do we have to standardize/normalize data?

I have to perform an independent group t-test and have unequal variances. From what I understand, the solution is to transform the data. To transform it, do I standardize it? Or simple use log10 to ...
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1answer
37 views

Do I have to standardize my data to calculate variance?

I have 2 groups/samples. Correct me if I'm wrong, but before doing an independent-group t-test we have to verify the homogeneity of variance with Hartley's F-max test. When doing this test, we have ...
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0answers
24 views

e1071: does the tune function do the scaling?

I'm using tune to choose the optimal gamma and cost hyperparameters for a RBF SVM. As feature scaling is essential, my question is: does the tune function do the scaling?
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0answers
48 views

How to name the concept of the mean shift divided by the standard deviation

In the context of a paper dealing with Statistical Quality Control, I am defining and using the concept of the mean shift divided by the standard deviation of a (normally distributed one-dimensional) ...
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1answer
26 views

Unstandardize the slope of standardised variables in a linear regression

If I standardize my dependent and independent variable, and run a linear regression between them, the slope estimate which I have will be standardised. The variables were standardised by subtracting ...
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0answers
25 views

Should I standardize or rescale with polynomial regression as alternative to difference scores?

I am working with a model that uses polynomial regression combined with response surface modelling as an alternative to difference scores in regression: ...
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0answers
11 views

Standardization and autoregressive process

If I have an autoregression with an exogenous variable and standardized the exogenous variable to better interpret the coefficients, can I standardize the dependent autoregressive component also so ...
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1answer
30 views

z-score and Normal Distribution

I have what is probably a pretty stupid question but for whatever reason I have not been able to find an answer so here goes.... It's my understanding that a z-score can only be calculated and ...
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1answer
33 views

Is standardisation and normalisation of data required before clustering when I have only 1 variable?

I have a data with only 1 variable. I need to use K-means clustering on it. Do I need to apply normalisation and/or standardisation on the data?
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16 views

transforming of standardised effect size in MuMIN package

I ran the following model ...
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1answer
74 views

lmer: standardized regression coefficients

I have analyzed some data (the exact nature of which, I assume, is irrelevant for this question) using linear mixed effects models with the lmer() function from lme4. There has been at least one ...
2
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1answer
131 views

Standardized coefficients for linear models with numeric and factor variables in multiple linear regression using scale() function in R

I have on question regarding standardized coefficients (beta) in linear models. I have already asked one question here. From the answers I assume that I should use R's ...
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31 views

standardization within time series and across groups (nested data)

I read through the previous threads concerning standardization of variables, but unfortunately have not found an answer whether it is justifiable or necessary to z-standardize values across groups ...
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51 views

z scores, highest percentile ranking, different distributions

Let a value $x$ have a z-score of (say) $+0.10$. With respect to which distribution(s) can $x$ have the highest percentile ranking: normal, positively skewed, or negatively skewed?
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1answer
25 views

Symbol to indicate normalized or standardized variables

Is there a symbol to indicate that variables have been standardized? For example, if I have 2 different scoring functions Score1 and Score2. Let's say I want to form a combo score and show that the ...
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1answer
45 views

Standardized coefficient for a categorical variable in logistic regression

I would like to rank independent variables in a logistic regression model based on relative importance. I've read about standardizing the variables prior to entering them in the model. So in this ...
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0answers
36 views

R- yaimpute - standarize value before KNN for imputation

I need to impute data before running a logistic regression. I'm trying the package yaimpute but I realized that it doesn't standarize before imputing. I created a sample matrix to view so: ...
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0answers
9 views

WHO Z-scores for bench-marking child growth: usage and interpretation

I have a data set which consists of two disjoint groups of children. I would like to compare the nutritional statuses of the two groups. Luckily, I have some anthropometrical measurements of the ...
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0answers
36 views

How to interpret the regression slope of standardised variables

my y variable is crop production (in kg/ha) and x variable is rainfall (mm). In a linear regression, if the slope is 0.5. I would say, 'if rainfall increases by 1 mm yield increases by 0.5 kg/ha.' ...
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3answers
49 views

Compare influence of same set of independet variables on two different dependet variables

I'm currently doing two multiple linear regressions. Each of them with the same set of predictors (measurements for real estate quality) $X_1,...,X_n$, but with different dependent variables (one of ...
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15 views

Standardizing variables at item or index level: Does it make a difference?

I'm running some multiple group CFA models comparing covariance structure by race/ethnicity and have survey data from 6th, 8th, 10th and 12th graders. My supervisor has told me to combine 6th and 8th ...
2
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0answers
133 views

Proper use of the coefficient of variation

I have a variety of samples, each with a different standard deviation and mean. The coefficient of variation $CV$ = ${\sigma} / {\mu}$ defines the amount of variation in a population or sample around ...
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2answers
188 views

Does feature standardization always make sense?

I wonder if feature scaling like this makes always sense for neural networks: Let $T$ be the training set and $x_i \in \mathbb{R}^n$ with $d_i \in T$ be the feature vector of $d_i$. Then add another ...
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0answers
35 views

standardization to obtain unit variance

I've come across some papers in where certain forecast errors are standardized to have unit variance. Unfortunately that's the only information they provide and I have no idea on how to ...
2
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1answer
70 views

Question about standardizing in ridge regression

Hey guys I found one or two papers which use ridge regression (for basketball data). I was always told to standardize my variables if I ran a ridge regression, but I was simply told to do this because ...
2
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1answer
253 views

How to standardize data

I have the test scores of two groups, say A, and B. And the former consists of 186 individuals whereas the latter only has 100. The test scores range from 1 to 12, and because group A has more people, ...
2
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1answer
175 views

Standardizing before/after/at all when using multi-class LDA for pre-processing step

If a multi-class Linear Discriminant Analysis (or I also read Multiple Discriminant Analysis sometimes) is used for dimensionality reduction (or transformation after dimensionality reduction via PCA), ...
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20 views

Standardising data within-subjects when analysing distributions

Analysing behavioural data, Spivey, Grosjean and Knoblich, (2005) wanted to show that their results came from a unimodal distribution, rather than from averaging over subpopulations in a bimodal ...
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36 views

Weighting, standardize, transforming data before for Multivariate ANCOVA

My question is in regards to data manipulation prior to Multivariate ANCOVA. My research focuses on crustacean eggs. The model involves a covariate and 2 x independent variables and 4 dependent ...
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1answer
33 views

Standardizing single coefficient in multivariate analysis

I have panel data and for the I have a following equation $$ logY = \beta_1 + \beta_2 logX + \beta_3 m logW $$ Problem is with $\beta_3$ coefficient. Since m is outside the log and it is a very ...
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1answer
84 views

Feature Normalization/Standardization before or after Feature Selection?

Should the process of feature normalization/standardization be done before or after the feature selection process?
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1answer
25 views

Does a time-series have to be stationary before you calculate a z score or t score?

It's been a long time since basic statistics. I have a financial time-series that exhibits exponential growth. Before I standardize, do I have to make the time-series stationary? Before I ...
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0answers
29 views

Centering vs. Standarizing which one is better? [duplicate]

Two approaches have been proposed in order to overcome the issue of multicollinearity if we have interaction variables which are mean centering and standardizing (z scores). You can check No.2 in this ...
3
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1answer
74 views

Intercept from standardized coefficients in logistic regression

I have fit a logistic regression model with original y and standardized x variables. Slope coefficients can be easily converted back to their original scale by $\beta^*_j/\sigma_{x_j}$ where ...
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0answers
25 views

How to standardize a variable an its power term?

In an regression analysis it is sometimes valuable to introduce power terms as predictor variables. Age is a good example in the social sciences. I know there is an general debate about introducing ...
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2answers
92 views

Standard method for calculating contribution of individual variable to outcome

I'm looking at the change in vote shares for an election between two periods. I'd like to say something about the contribution of one variable in particular towards the election swing I document. I'm ...
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1answer
64 views

Interpretation with training and test set with standardized variables

I've standardized all the variables (even the response variable) and then I've split my data into a training and test part. And for example, I've got the following model based on my TRAINING set: y = ...
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1answer
55 views

Standardizing feature vectors for regression

Suppose I have a data set with the following structure: Each row of the data set indexes a town. The first column/feature variable is the total population while the other feature variables include ...