Resampling for limited data

Advanced Probability: Uncertainty in Data

Maarten Van den Broeck

Senior Content Developer at DataCamp

What is resampling?

• How many marbles of each color?
• Estimate without counting
• Solution: take repeated samples and record colors

Resampling techniques

• Bootstrapping
• Cross-validation
• Synthetic sampling

Bootstrapping

Cross-validation

Synthetic resampling

Example: fraud detection

• Fraudulent transactions are rare
  • Models predict all transactions as safe
• Generate synthetic fraud cases
  • Model can learn fraud patterns

Example: fraud detection

• Starting situation:

  • 1,000,000 transactions per month
  • 1,000 or 0.1% classified as fraudulent

• Synthetic sampling:

  • Increase fraudulent samples to 10,000 or 1%

Let's practice!

Advanced Probability: Uncertainty in Data