Using modified z-scores with PyOD
It is time to unleash pyod on outliers. We use the MAD estimator from pyod to utilize modified z-scores. The estimator already uses the median_abs_deviation function under the hood, so it is unnecessary to repeat the previous steps.
The MAD estimator has already been loaded from pyod.models.mad and the data is available as prices.
Cet exercice fait partie du cours
Anomaly Detection in Python
Instructions
- Initialize
MAD()with athresholdof 3.5. - Reshape
pricesto make it 2D. - Generate inlier/outlier labels on
pricesby fitting and predicting usingmadsimultaneously. - Subset
labelsfor outliers, which are denoted as 1.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
# Initialize with a threshold of 3.5
mad = ____(____=____)
# Reshape prices to make it 2D
prices_reshaped = ____.____(-1, 1)
# Fit and predict outlier labels on prices_reshaped
labels = ____
# Filter for outliers
outliers = ____[____ == ____]
print(len(outliers))