Skill readiness test

Principal Machine Learning Engineer, Agentic AI at Zillow

2 questions, about 3 minutes. This is a diagnostic, not a certification — it estimates your skill readiness, it does not guarantee you are qualified for or will be hired into this role.

1. Which library is most commonly used for tabular data manipulation in Python?

pandas flask requests pytest

2. What does `df.groupby('region')['sales'].sum()` return?

The total sales across the whole dataframe Total sales summed for each distinct region A count of rows per region An error, because groupby requires two columns