Compute 3-Day Rolling Revenue Averages with Pandas
Company: Amazon
Role: Data Scientist
Category: Data Manipulation (SQL/Python)
Difficulty: Medium
Interview Round: Onsite
sales
+------------+-----------+-------+---------+
| date | product_id| units | revenue |
+------------+-----------+-------+---------+
| 2023-01-01 | 101 | 5 | 100.0 |
| 2023-01-02 | 101 | 3 | 60.0 |
| 2023-01-03 | 102 | 8 | 160.0 |
| 2023-01-04 | 101 | 2 | 40.0 |
| 2023-01-05 | 102 | 7 | 140.0 |
+------------+-----------+-------+---------+
##### Scenario
Cleaning and aggregating daily sales data to compute rolling revenue trends per product.
##### Question
Using Python/pandas on the sales table, compute the 3-day rolling average of revenue for each product_id, pivot the result so dates are rows and product_ids are columns, and include total units sold per product.
##### Hints
Show imports, set date index, sort, groupby+rolling, pivot, merge totals; code should run end-to-end.
Quick Answer: This question evaluates proficiency with Python pandas for time-series data manipulation, specifically group-wise aggregation, rolling-window calculations, pivoting, and merging summary statistics.