Day 21 - Statistical vs Probabilistic Pattern Matching in LLMs
Context:
In my previous post, I learned that Probabilistic Pattern Matching is used by LLMs to predict the next word. Today, I explored how models learn patterns during training — and discovered the role of Statistical Pattern Matching.
What I Learned:
- Statistical Pattern Matching:
- Builds an internal “map” of relationships between words, tokens, and contexts.
- Example: The model learns that “river” often appears near “water” or “bank.”
- Probabilistic Pattern Matching:
- Given a context, predicts the most likely next word by ranking probabilities.
- Example: "The cat sat on ___" mat (60%), floor (25%), spaceship (15%) → selects "mat"
- In short:
- Statistical = The How (internal learned structures).
- Probabilistic = The What (final output choice).
Why It Matters for QA / AI Testing:
- Understanding both mechanisms helps testers anticipate why LLMs produce certain outputs.
- Statistical learning explains biases from training data; probabilistic prediction explains variability in responses.
- Useful for designing prompts and validating AI behavior under different contexts.
My Takeaway:
LLMs learn patterns statistically and predict outputs probabilistically — two sides of the same coin powering AI responses.