Questions tagged [data-transformation]

Mathematical re-expression, often nonlinear, of data values. Data are often transformed either to meet the assumptions of a statistical model or to make the results of an analysis more interpretable.

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Efficient storage of functional data

I have access to a sample (size $N$) of functional data. Each observation corresponds to $C$ functions. Each function $f_{n,c}$ is represented by $T_n$ points for $1\geq n \geq N, 1\geq c \geq C$. All ...
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Why variable representation plays a role in prediction?

I am working on binary classification using a random forest, where the data have 977 records and 6 columns. The class ratio is 77:23. I have two derived input variables. One variable is called ...
• 1,780
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Can a transformed variable's SE be meaningfully interpreted?

Suppose, for simplicity, I have a simple linear regression model, and I have transformed the response variable by taking the square root. The pre-transformed standard error is equal to 17, and the ...
1 vote
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Scaling a single continuous variable

I have a basic question. I know you have to scale your variables (fixed effects) when you have several continuous fixed effects, to be able to compare them. However, if I only have one continuous ...
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Separating datasets vs one dataset with extra categorical feature

I have regression/classification problem. Dataset contains data from 4 sensors on 4 positions (1,2,3,4). Processes measured on all 4 positions are equivalent and same label and features describe all 4 ...
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Mixed ANOVA - Can We Standardize After Box-Cox Transformed Values

in our mixed ANOVA (2 timepoints, 3 interventiongroups, so 2x3 factorial ANOVA), the homogeneity of the residual variance was violated as indicated by significant levene tests, for the post-...
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Meta-analysis with ratio data

I am currently performing a meta-analysis where the outcome of interest is the ratio between the concentration of two sugars in urine/plasma (i.e. the results of dual-sugar test; see: https://doi.org/...
13 views

Moving columns under other columns in R [migrated]

I have to work with an existing dataset and want to move the content of some columns (in this example the content of columns F to J) under the content of columns A to E so that the length of the ...
13 views

Regression with independent variables as percentages [duplicate]

I'm trying to run a regression analysis where my dependent is number of deaths and some of my independent variables are things like: poverty rate (Ex - 0.16, 0.09), incarceration rates (Ex 0.0042, 0....
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Which method of logarithmic transformation is correct to use in linear model?

I try to do a simple linear model with logarithmic transformation of y values. I found that depending on which method I use the results differ and I don't ...
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1 Stationary time series, 1 non stationary: do I need to transform BOTH, OR can I use VAR with 1 transformed and 1 stationary variable?

I am doing a time series forecast using VAR. I have 2 time series, "orders" and "calls" The orders time series is stationary The calls time series is non-stationary Let's say I use ...
36 views

what data transformation function will reverse the order in the original data?

I want to apply a data transformation function that produces value between 0 and 1 and also the order is reversed. The max becomes min after transformation and the minimum becomes max value. Assuming ...
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Does combining train and test data introduces any potential bias?

Given an estimator $f$ and a dataset $D$ with $k>2$ classes where $S_{train}$ denotes the train set and equivalently $S_{test}$ the test set. Suppose we want to transform the problem and instead of ...
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transformation of a kernel density estimate to uniform distribution

I am interested in estimating the expected value of a function, $f(x)$ with respect to a probability density function, $P(x)$. I am exploring a method that requires I change variables from the ...
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uniformly sample from gaussian distributed data

I have data that is roughly gaussian distributed, bounded on a range of [x0, x1], w/ mean m and stadard deviation s. I want to ...
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E(log(x)) to E(x) [duplicate]

Sorry if this is a straightforward question, but I have tried digging into econometrics book and cannot find anything about it. I worked on a model with ...
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How to use RFM along with Predictive model?

I am looking to segment my customers based on their transactional data with us. Based on google search, I came to know about RFM matrix, which records Recency, Frequency and Monetary value-based ...
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Rule based label - For attrition risk

I have 3 domains of supplier data (Jan 2017 to Jan 2022) and they are as follows a) Purchase data - Contains all the purchase (of product) data made by the suppliers with us. It contains columns such ...
• 1,780
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Why logit transform explanatory variable restricted between $0$ and $1$ only if it is close to $0$ or $1$?

In Bayesian Data Analysis 3rd edition chapter 14 on linear regression they write Since the explanatory variable is restricted to lie between 0 and 1 (recall that we have excluded uncontested ...
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fit transform so that variance is independent of mean as much as possible when only ranks are available

set.seed(0) n=10000 x=rnorm(n) m=10 y=replicate(m, x+rnorm(n)) scaledrank=function(x) { n=nrow(x) apply(x, 2, function(v) rank(v)/(n+1)) } X=scaledrank(y) ...
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Why does my data look the same after log, root, Box-Cox transformations?

I have to forecast the amount of cars sales for the next 12 months. The data I have gathered are from 2013-2021 (108 months). This is what the plot of my data looks like using Rstudio and its ...
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