Data Processing Computer-Based Test On Data-Processing 3 — Questions and Answers
Question 1: Which algorithm is commonly used to sort large datasets stored on disk (external sorting)?
- Bubble sort
- Quick sort
- Merge sort (Correct answer)
- Insertion sort
Correct answer: Merge sort
Merge sort is well-suited for external sorting because it processes data in sequential passes, which minimizes disk I/O.
Question 2: In the context of databases, ACID properties ensure:
- Fast query execution
- Reliable transaction processing (Correct answer)
- Efficient data compression
- Automatic data replication
Correct answer: Reliable transaction processing
ACID (Atomicity, Consistency, Isolation, Durability) properties guarantee that database transactions are processed reliably.
Question 3: What is the primary purpose of data masking in a processing environment?
- Improving query performance
- Protecting sensitive data by replacing it with realistic fictional values (Correct answer)
- Reducing the size of datasets
- Detecting anomalies in data streams
Correct answer: Protecting sensitive data by replacing it with realistic fictional values
Data masking substitutes sensitive information with realistic but fictitious data so non-production environments cannot expose real values.
Question 4: A hash table achieves average-case O(1) time complexity for lookups because:
- It keeps all elements sorted in memory
- It uses a hash function to map keys directly to storage locations (Correct answer)
- It uses binary search to locate elements
- It stores elements as a balanced tree
Correct answer: It uses a hash function to map keys directly to storage locations
A hash function computes an index into an array, allowing near-instant access without scanning other elements.
Question 5: In stream processing, a 'tumbling window' differs from a 'sliding window' in that it:
- Overlaps with adjacent windows
- Has no fixed size
- Does not overlap — each window is a distinct, non-overlapping interval (Correct answer)
- Processes only the most recent event
Correct answer: Does not overlap — each window is a distinct, non-overlapping interval
Tumbling windows divide a data stream into fixed, non-overlapping time intervals, while sliding windows can share events between windows.
Question 6: Which of the following is an example of unstructured data?
- A CSV file with sales transactions
- A relational database table of customer records
- A free-text email message (Correct answer)
- An XML document with a defined schema
Correct answer: A free-text email message
Free-text email messages lack a predefined schema or structure, making them unstructured data.
Question 7: What does 'data lineage' track in a data processing system?
- The physical location of data on storage media
- The origin, movement, and transformation of data over time (Correct answer)
- The number of users who have accessed a dataset
- The encryption algorithm applied to each data field
Correct answer: The origin, movement, and transformation of data over time
Data lineage documents where data comes from, how it moves through systems, and how it is transformed, enabling auditability.
Data Processing Computer-Based Test On Data-Processing 3
Which algorithm is commonly used to sort large datasets stored on disk (external sorting)?