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TDS · Data sourcing & cleaning

8 questions · 9 marks · 4 papers

Answer key

Indian Institute of Technology Madras

BS Degree Programme · Examination & Study Paper

Tools in Data Science

Data sourcing & cleaning

Official Paper

Examination Instructions & Guidelines

Solve on notebook/paper first before checking solutions.
MCQ: Exactly 1 option is correct. Negative marking applies.
Scientific calculator allowed for all calculations.
Official answer key is sealed at the end of this sheet.

End Term · 31 Aug 2025 (FN)End Term

Q1MCQ1 Mark·Choose one option
Asked 3 times Key ↓
When cleaning a dataset with company names like "Microsoft Corp", "Microsoft Corporation", "MSFT", which OpenRefine technique would be most effective?
1. ASimple find and replace operations
2. BClustering algorithms with fingerprinting and n-gram comparison
3. CRegular expression matching only
4. DManual standardization
Q2MCQ1 Mark·Choose one option
Asked 2 times Key ↓
1. A
2. B
3. C
4. D

End Term · 31 Aug 2025 (AN)End Term

Q3MCQ1 Mark·Choose one option
Key ↓
When standardizing inconsistent date formats in a dataset using OpenRefine, which transformation approach is most effective for handling multiple date patterns?
1. ASimple text replacement operations
2. BGREL expressions with multiple conditional date parsing functions
3. CManual editing row by row
4. DExport to Excel and use built-in date formatting
Q4MCQ2 Marks·Choose one option
Asked 2 times Key ↓
For a web scraper that encounters 429 (Too Many Requests) status codes, which response strategy demonstrates ethical behavior?
1. ASwitch to different IP addresses to bypass the limit
2. BImplement exponential backoff starting with the Retry-After header value, reduce request frequency permanently
3. CContinue scraping but filter out 429 responses
4. DUse browser automation to appear more human-like

End Term · 13 Apr 2025 (FN)End Term

Q5MCQ1 Mark·Choose one option
Asked 2 times Key ↓
You receive a tab-delimited file where some numeric fields are interpreted as dates (e.g., "3/10" becomes "March 10" in Excel). What is the most effective way to handle this in Text to-Columns?
1. AChange the delimiter to commas before opening the file
2. BFormat the column as Text before applying Text-to-Columns
3. CUse the General data format option in Text-to-Columns
4. DManually change the affected cells back to numbers after splitting
Q6MCQ1 Mark·Choose one option
Asked 3 times Key ↓
A data analyst receives a messy dataset with inconsistent company names like "Apple", "Apple Inc.", and "Apple Incorporated". Which tool would best standardize these entries?
1. AExcel's Find and Replace
2. BOpenRefine's clustering feature
3. CPython's string manipulation
4. DManual editing

End Term · 22 Dec 2024 (FN)End Term

Q7MCQ1 Mark·Choose one option
Asked 2 times Key ↓
1. AThe numeric part of the order (123, 456, 789, 101)
2. BOnly the first character of the order ID (O, O, O, O)
3. CThe column will remain unchanged
4. DEach character of the order ID will be split into separate cells (O, r, d, e, r, I, D, 1, 2, 3)
Q8MCQ1 Mark·Choose one option
Asked 3 times Key ↓
You have a dataset of customer names that includes duplicates due to inconsistent capitalization and extra whitespace (e.g., 'John Doe', 'JOHN DOE', 'John Doe'). Which of the following tools would be best for cleaning and de-duplicating this data?
1. AOpenRefine
2. BTableau
3. CMySQL
4. DMicrosoft Excel

Official Key

Master Answer Key & Explanations

Official answer keys from IIT Madras BS past papers. Click any question to review.

Reveal Key

Q1B

Q2B

Q3B

Q4B

Q5B

Q6B

Q7D

Q8A

Questions and answer keys are reproduced from the official IIT Madras BS papers. Topics and repeated question types are BTechi’s own grouping. BTechi is not affiliated with IIT Madras.