Questions tagged [under-sampling]

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How R randomforest sampsize works?

I am working on a predictive model (imbalanced data) and trying to undersample the majority class data. I wanted to get the representative sample of my majority class and somehow came to know about R'...
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36 views

What are some “not so common” methods for dealing with unbalanced data?

When we talk about unbalanced data, we usually think about SMOTE, resampling and so on. Usually the methods mentioned here: https://www.kaggle.com/rafjaa/resampling-strategies-for-imbalanced-datasets. ...
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20 views

How to select a classifier from the set of classifiers resulted from different random undersamplings with different accuracies?

I have a labeled two-class training set and a test set. My training set data is imbalanced. I want to train a classifier using the training set and evaluate it's accuracy using the test set. Before ...
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96 views

What's a range of good F1 scores?

I have watched a lot of videos on machine learning and in terms of F1 scores, all are different. One video says that an F1 score of .8 is bad, but another says an F1 score of .4 is excellent. What's ...
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15 views

Limits of oversampling

I have a dataset with an event rate of less than 0.3 percent. To improve the modeling results, I did some oversampling using SMOTE. I initially oversampled so that the event rate increases 10 times to ...
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30 views

What causes the high OOB-error for randomForest() in R?

I'm trying to perform a random forest in R on a dataset with 16364 observations (after undersampling), using the function randomForest(). But my results look really weird: What could have caused this?...