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Questions tagged [down-sample]

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Do ANOVA & MANOVA require balanced levels?

I have one independent variable with two levels, or categories, and four dependent variables. When doing a MANOVA or ANOVA test, how important is it for the number of observations in each category to ...
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0answers
36 views

While dealing with imbalanced classes, to what extent can we upsample a minority class? [duplicate]

I have my training data with the following approximate distribution: Negative events : 90,000 positive events : 5,000 Training a model would require to oversample the minority class (and might also ...
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1answer
48 views

Does downsampling decrease the entropy of the data?

Suppose we have an $n-dim$ time-series $X={x_1, x_2, \cdots, x_n}$ and we resample it to $m-dim$, $\hat{X}={\hat{x}_1, \hat{x}_2, \cdots, \hat{x}_m}$, where $m < n$. Can we say this downsampling ...
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22 views

Resampling imbalanced data in a multi-view scenario

Assume a multi-view scenario, where multiple views of the same entity are available. If each data pair is assigned a label and the resulting scenario is highly imbalanced, what are proper ways of ...
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0answers
34 views

should I resample/downsample the patients in the control arms?

I have retrospectively collected clinical data of two sets of patients, one set with the diagnosis of tumor A (group A) and the other with tumor B (group B). There're 90 patients in group A, and 1100 ...
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1answer
424 views

Is Tomek Link undersampling the same as Edited Nearest Neighbours with 1 neighbour?

From what I've read I've understood that undersampling the majority class with Tomek Links or Edited Nearest Neighbours with 1 neighbour should yield the same result. However, I've tried it on this ...
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1answer
171 views

Statistics of bootstrapped subsampled data

Scenario I have a treatment (T) and control (C) sample. In my T sample, I have 600 observations, and in my C sample, I have 250 observations. Because the number of observations might be important ...
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0answers
342 views

Convert predicted probabilities after downsampling to actual probabilities in classification

If I use undersampling in case of an unbalanced binary target variable to train a model, the prediction method calculates probabilities under the assumption of a balanced data set. I discovered two ...
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1answer
240 views

Kappa and downsampling, selection of data set

I have a unbalanced data set and use Cohen's kappa and AUC as performance measure. Without down sampling the Kappa value is around 0.85, with random down sampling it is 0.95. and with a house-made ...
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1answer
96 views

Correlation between vectors with non-matching y values without using interpolation

Is there a way to calculate the correlation between two time series that have been adaptively downsampled and thus (may) have different y values? This is easiest to explain with an example, so ...
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0answers
148 views

Does downsampling affect regression results?

How is linear regression affected by downsampling the explanatory variable? To be more precise, I would sort all the values of $x$, and then split into a a number bins with equal number of points in ...
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0answers
499 views

How to use cross validation when you have missing data & rare events?

I am trying to use repeated cross validation to test my classifier. Moreover, I want to use imputation due to missing values and downsampling due to unbalanced data (I have 88% of my data in the ...
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0answers
227 views

Bias from stratified sampling

Due to a lack of significance and the large size of the dataset (which had binomial responses with 20,000 responses out of a sample of 15,000,000) my peer has used random sampling to reduce the amount ...
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0answers
2k views

How to determine the correlation between data sets with the same period but different sample rates?

I am trying to determine the correlation between two sets of data points which span the same time period (20 minutes) but have different resolutions. The first set was recorded at 1-minute intervals, ...
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0answers
129 views

Numerical differentiation (derivative) and downsampling

I have some time course data which I would like obtain the first derivative of. As it seems quite difficult to model, I do not intend to fit a function to it, but rather compute the first derivative ...