Lesson ProgressPhase 5 of 6
Phase 5Assessment
Assessment: Data Cleaning and Analysis
Technical check and business communication artifact
Phase 5: Audit and Explain
Verify Your Work and Document the Process
Check that cleaning worked. Then create a brief memo explaining what you did and why it matters.
Data Cleaning Audit Check
Test your understanding of data quality decisions and documentation requirements.
1. After Remove Duplicates, your row count went from 500 to 485. What does this tell you about your data quality?
2. You find 12 rows with blank category values. What's the best approach?
3. An investor asks: 'How did you handle the data quality issues?' What documentation should you show?
4. After cleaning, you try to calculate AVERAGE(Price) but get an error. What's likely wrong?
0 of 4 questions answered
Artifact Task: Data Cleaning Memo
Write a 3-4 sentence memo to explain your cleaning work:
- What did you clean? (e.g., removed duplicates, trimmed spaces, fixed price format)
- How many rows affected? (before/after counts)
- What's ready for analysis now? (what the cleaned data can do)
- Any remaining issues? (known limitations to flag)
Example:
"Removed 15 duplicate transactions (500→485 rows). Trimmed spaces from product names and removed $ symbols from prices. Data is now ready for statistical analysis. Note: 12 rows have unknown categories—flagged as 'Unknown'."
Performance Standards
- Investor‑Ready: Clean data, documented audit trail, no calculation errors
- Proficient: Mostly clean with minor issues noted
- Developing: Missing documentation or obvious cleaning gaps
Career link: Consultants always document data cleaning steps. It's how others verify your work.