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

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43 views

Is the covariance of standardized variables the correlation?

I have a basic question. Say I have two random variables, $X$ and $Y$. I can standardize them by subtracting the mean and dividing by the standard deviation, i.e., $X_{standardized} = \frac{(X - ...
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1answer
35 views

Recovering original regression coefficients from standardized

Suppose I use Least Squares to estimate coefficients in the standard linear model with design matrix $X$'s columns standardized, so the model is $$ E[y] = X^*\beta^* $$ where $X^*$ is $X$ with columns ...
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20 views

Standardize within cohort or standardize within entire sample?

Suppose I'm interested in regressing variable A on variable B. I have two cohorts and want to be sure that there is not an interaction between cohort and variable B, so I include that in the ...
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19 views

Scaling factor in R?

I am implementing a logit model on fraud detection data set which is having several attributes.Target column is truth or fraud.Data contains transaction amount is one of attributes.I generally scale ...
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1answer
21 views

Deriving the mean from a raw and standardized score

My son has received 52 marks in a test. This has been standardized, using a mean of 100 and a standard deviation of 15, as 102.27 What is the mean mark, and how many marks would he have needed to get ...
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27 views

Confidence Intervals of a Given Width

I'm working through some questions on confidence intervals. My answer doesn't match the book, but the book's answer was a number I had a few steps before the end. I have ten numbers which are a ...
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30 views

Standardization/Centering of Longitudinally-measured variable

Could someone possibly help me with the following issues that I am mentally stuck at? Thanks so much! I have 200 variables M1, M2, .... Mx. Each is measured at three time points 0, 30, 120 min. The ...
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1answer
29 views

Should I standardize age in the following situation?

I am a graduate student in biochemistry, and I am looking at cancer death rates for the Canadian population in 2010. Basically, I have acquired from Statistics Canada: 1) The estimates of individuals ...
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51 views

How to calculate age and sex-adjusted z-scores in SPSS

I have a large data set in SPSS which includes triceps skinfold measurements for children at various ages. I would like to create z-scores for these measurements which adjust for sex and age... is ...
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11 views

Student t distribution: standardization [duplicate]

I got a question concerning the standardization of a student t distribution. I see that the "plain vanilla" t distribution has density $f(x|\nu)=\frac{\Gamma(\frac{\nu+1}{2}) ...
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29 views

Standardization (z-score) across the “Samples” or across the “variables”?

I found in literature that one of the most common way of standardization data is to compute z-scores (mean subtraction and division by standard deviation). Can anybody tell me if it is ok to compute ...
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38 views

OLS with ordinal dependent variable - do the coefficients mean anything?

I currently read a paper in which the author has asked people 3 different questions regarding their life satisfaction, all of which are to be rated on a four point scale: 1) very low, 2) low, 3) high, ...
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25 views

Z-score across the “Samples” or across the “variables”?

I found in literature that one of the most common way of standardization data is to compute z-scores (mean subtraction and division by standard deviation). Can anybody tell me if it is ok to compute ...
0
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1answer
36 views

Some issues with standardized variable in a regression analysis

I'm solving this multiple choice question on the properties of a standardized variable. Two of the possible options (which are wrong but look right to me) are 1. It is always normally distributed and ...
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0answers
54 views

How to destandardize PCA scores in R

I ran PCA in R using the principal() function in the "psych" package. Suppose my dataset is called "data" (118 rows and 8 columns). The 8 variables are answers from a questionnaire, with a scale that ...
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1answer
41 views

Standardizing sample factor scores: population or standard deviation

Please note: This question pertains to Q Methodology, a research method used to study people's subjectivity. Q embodies ontological and epistemological assumptions that sometimes differ markedly from ...
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1answer
38 views

How does data standardization affect a classifier?

How does standardization of data (subtracting the mean, dividing by standard deviation) affect classifiers? Namely, how (if at all) do different types of classifiers get affected by such an operation? ...
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1answer
56 views

Multicollinearity and interaction terms

My dataset has 2734 observations (but in some speficitations, that number reduces to 1280). I also have interaction terms (in some specifications, even fourth-order terms). As far as I know, ...
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24 views

Interpreting standardized log coefficients in OLS

I used the log for my dependent variable as well as for some independent variables. Then I standardized all variables. Now I'm not sure how to interpret the coefficients. Are the log and non loged ...
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11 views

Creating A weighted Scorecard using Stats

Im new to forum and have tried reading some articles to solve my problem but had trouble understanding some of it and others might not have been completely relevant. Below I will outline my problem ...
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32 views

Standardizing variables and interpreting coefficient estimates

I standardized my explanatory variables so that each variable has a mean of 0 and standard deviation of 1 to improve convergence of the fitting algorithm and putting the estimated coefficients on the ...
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31 views

Interpretation of scaled data in a logistic regression analysis

I have a variable (distance to road; measurement=meters; see below) that contains a right-skew and percentage data (0-100% based on amount of habitat in a moving window; see example below) in a ...
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0answers
26 views

In penalized regression models, should binary predictors be standardized?

It is generally agreed that in penalized regression models, such as ridge regression, the lasso, and the elastic net, one should standardize the predictors (such as dividing each by its SD) so that ...
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1answer
76 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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69 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
49 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
61 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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13 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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8 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
55 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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56 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
48 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
65 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
26 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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81 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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65 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
47 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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43 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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72 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
43 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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37 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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14 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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2answers
76 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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0answers
56 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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23 views

transforming of standardised effect size in MuMIN package

I ran the following model ...
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1answer
169 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 ...
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1answer
418 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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53 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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64 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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34 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 ...