MCQs

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Overall MCQs for Reference

1. Which of the following is not a typical SQL aggregation function?
   a. SUM()
   b. MAX()
   c. MEAN()
   d. AVG()
   Answer: c. MEAN()geeksforgeeks+1​
2. The COUNT(*) function in SQL returns:
   a. The number of rows including NULLs
   b. Only the non-NULL rows
   c. The distinct count of values
   d. The sum of all values
   Answer: a. The number of rows including NULLsw3schools+2​
3. Data aggregation can be categorized by:
   a. Time
   b. Spatial
   c. Hierarchical
   d. All of the above
   Answer: d. All of the abovesentinelone+1​
4. Which aggregation function calculates the average value of a numeric column?
   a. COUNT()
   b. MAX()
   c. AVG()
   d. MIN()
   Answer: c. AVG()dremio+1​
5. What does the GROUP BY clause achieve in SQL aggregation?
   a. Filters data
   b. Groups rows with same values
   c. Deletes duplicates
   d. Calculates totals
   Answer: b. Groups rows with same valuesgeeksforgeeks+1​
6. What type of data aggregation is used to analyze trends over years or months?
   a. Time-based aggregation
   b. Spatial aggregation
   c. Categorical aggregation
   d. Manual aggregation
   Answer: a. Time-based aggregationcoresignal+2​
7. Which aggregation type involves grouping data based on regional location?
   a. Time aggregation
   b. Spatial aggregation
   c. Manual aggregation
   d. Automated aggregation
   Answer: b. Spatial aggregationgeeksforgeeks+2​
8. What is the role of the HAVING clause in SQL aggregation?
   a. Sorts data
   b. Applies predicates after grouping
   c. Selects distinct rows
   d. Calculates averages
   Answer: b. Applies predicates after groupingsanfoundry​
9. Aggregate functions in SQL usually ignore NULLs, except:
   a. COUNT()
   b. SUM()
   c. AVG()
   d. MIN()
   Answer: a. COUNT()scribd+1​
10. Which function would provide the smallest value in a dataset?
    a. AVG()
    b. SUM()
    c. COUNT()
    d. MIN()
    Answer: d. MIN()dremio+1​
11. In which scenario is hierarchical aggregation preferred?
    a. Complex organizational structures
    b. Flat data tables
    c. Simple total calculation
    d. Duplicate removal
    Answer: a. Complex organizational structuressentinelone​
12. Which aggregate function is used to calculate total values in a column?
    a. COUNT()
    b. AVG()
    c. SUM()
    d. GROUP BY
    Answer: c. SUM()w3schools+2​
13. Categorical aggregation is best for:
    a. Comparing segment performances
    b. Calculating overall total
    c. Removing duplicates
    d. Calculating geographical patterns
    Answer: a. Comparing segment performancessentinelone​
14. Which aggregation method uses two or more categories to create a summary table?
    a. Cross-tabulation aggregation
    b. Hierarchical aggregation
    c. Time aggregation
    d. Spatial aggregation
    Answer: a. Cross-tabulation aggregationsentinelone​
15. What type of aggregation combines data from multiple sources into a single dataset?
    a. Data fusion
    b. Time aggregation
    c. Manual aggregation
    d. Categorical aggregation
    Answer: a. Data fusionowox​
16. Which SQL clause is most often paired with aggregate functions like COUNT or SUM?
    a. WHERE
    b. GROUP BY
    c. HAVING
    d. DISTINCT
    Answer: b. GROUP BYsecoda+2​
17. Data binning is an aggregation technique that:
    a. Groups continuous data into intervals
    b. Calculates averages
    c. Removes NULLs
    d. Summarizes overall values
    Answer: a. Groups continuous data into intervalsowox​
18. Which aggregate function returns the largest value in a column?
    a. COUNT()
    b. MAX()
    c. AVG()
    d. SUM()
    Answer: b. MAX()geeksforgeeks+2​
19. Pivot tables in aggregation are used for:
    a. Reshaping and summarizing data
    b. Sorting rows
    c. Calculating distinct values
    d. Removing duplicates
    Answer: a. Reshaping and summarizing datadatawars+1​
20. Attribute aggregation involves:
    a. Summarizing data based on shared features
    b. Removing duplicates
    c. Calculating averages
    d. Sorting results
    Answer: a. Summarizing data based on shared featuresowox​
21. Weighted aggregation adjusts for:
    a. Relevance or importance of data points
    b. Only categorical variables
    c. Timeliness of data
    d. Spatial clusters
    Answer: a. Relevance or importance of data pointsowox​
22. A distinct aggregation in SQL performs:
    a. Counts unique values excluding duplicates
    b. Calculates sums
    c. Averages all values
    d. Removes NULLs
    Answer: a. Counts unique values excluding duplicatesw3schools+1​
23. Which function would ignore NULL values by default?
    a. AVG()
    b. COUNT(*)
    c. COUNT(column_name)
    d. MIN()
    Answer: a. AVG()dremio+1​
24. Manual aggregation is described as:
    a. Manually combining and summarizing data
    b. Using machine learning models for aggregation
    c. Applying SQL clauses
    d. Fetching data from APIs
    Answer: a. Manually combining and summarizing datacoresignal​
25. Which tool is commonly used for basic data aggregation and analysis?
    a. Microsoft Excel
    b. Photoshop
    c. WordPress
    d. GitHub
    Answer: a. Microsoft Excelcoresignal​
26. “Slice and Dice” refers to:
    a. Viewing aggregated data from multiple perspectives
    b. Calculating totals only
    c. Removing duplicates
    d. Summing categorical values
    Answer: a. Viewing aggregated data from multiple perspectivesowox​
27. Which Python library provides pandas DataFrame aggregation via .groupby()?
    a. pandas
    b. numpy
    c. matplotlib
    d. seaborn
    Answer: a. pandasdatawars​
28. Cross-tabulation aggregation usually results in:
    a. A summary table comparing variables
    b. Sorting of all entries
    c. Removal of duplicates
    d. Ignoring NULL values
    Answer: a. A summary table comparing variablessentinelone​
29. Data aggregation helps organizations:
    a. Generate meaningful insights
    b. Increase raw data storage
    c. Avoid data analysis
    d. Hide patterns
    Answer: a. Generate meaningful insightssentinelone​
30. Which method can you use to aggregate over a certain level of hierarchy?
    a. Hierarchical aggregation
    b. Spatial aggregation
    c. Time aggregation
    d. Boolean aggregation
    Answer: a. Hierarchical aggregationsentinelone​
31. Which is NOT an attribute aggregation technique?
    a. Weighting
    b. Binning
    c. Pivoting
    d. Deleting
    Answer: d. Deletingowox​
32. SUM(DISTINCT column_name) in SQL calculates:
    a. Sum of unique values
    b. Sum of NULLs
    c. Average of all values
    d. Total number of entries
    Answer: a. Sum of unique valuesgeeksforgeeks​
33. Which of the following is a direct benefit of automated aggregation?
    a. Saving time and reducing error
    b. Increased manual effort
    c. Decreased reliability
    d. Data duplication
    Answer: a. Saving time and reducing errorcoresignal​
34. In the context of aggregation, “binning” refers to:
    a. Categorizing continuous data into discrete intervals
    b. Combining sources
    c. Sorting alphabetically
    d. Filtering NULLs
    Answer: a. Categorizing continuous data into discrete intervalsowox​
35. A typical output of GROUP BY with aggregation would include:
    a. Summary statistics for each group
    b. Raw data rows
    c. Only unique values
    d. Only averages
    Answer: a. Summary statistics for each groupdremio+1​
36. In weighted aggregation, the result is influenced by:
    a. Assigned weights to each data point
    b. Grouping variables
    c. Duplicating rows
    d. Deleting missing values
    Answer: a. Assigned weights to each data pointowox​
37. Data fusion during aggregation is mainly conducted to:
    a. Enhance completeness and reliability of datasets
    b. Reduce dataset size
    c. Remove categorical variables
    d. Only calculate averages
    Answer: a. Enhance completeness and reliability of datasetsowox​
38. What is the main use of aggregation in data mining?
    a. Summarizing and transforming data for analysis
    b. Storage optimization
    c. Filtering unique rows
    d. Data visualization
    Answer: a. Summarizing and transforming data for analysisgeeksforgeeks​
39. When applying AVG() in SQL, which values are ignored?
    a. NULL values
    b. MIN values
    c. MAX values
    d. SUM values
    Answer: a. NULL valuesgeeksforgeeks+1​
40. Which aggregation type is best for studying demographic segments?
    a. Categorical aggregation
    b. Time aggregation
    c. Hierarchical aggregation
    d. Manual aggregation
    Answer: a. Categorical aggregationsentinelone​
41. In Python’s pandas, what does .agg() enable?
    a. Applying multiple aggregation functions to columns
    b. Only filtering values
    c. Sorting data
    d. Removing NULLs
    Answer: a. Applying multiple aggregation functions to columnsdatawars​
42. What is the result when using GROUP BY with COUNT(*)?
    a. The total number of rows in each group
    b. The sum of values per group
    c. The mean per group
    d. Unique values per group
    Answer: a. The total number of rows in each groupgeeksforgeeks​
43. The main advantage of automated aggregation tools is:
    a. Faster processing and error reduction
    b. Manual data entry
    c. More complex formulas
    d. Increased duplication
    Answer: a. Faster processing and error reductioncoresignal​
44. Data aggregation techniques improve analysis by:
    a. Making patterns and trends visible
    b. Hiding data
    c. Reducing analysis accuracy
    d. Focusing on individual points only
    Answer: a. Making patterns and trends visiblesentinelone​
45. Mean, sum, count, min, and max are examples of:
    a. Aggregate functions
    b. Selection clauses
    c. Sorting techniques
    d. Boolean operations
    Answer: a. Aggregate functionsw3schools+2​
46. Which SQL clause combines with aggregation to filter group results?
    a. HAVING
    b. WHERE
    c. ORDER BY
    d. DISTINCT
    Answer: a. HAVINGsanfoundry+1​
47. In aggregation, pivoting refers to:
    a. Rotating and summarizing data dimensions
    b. Removing NULLs
    c. Sorting alphabetically
    d. Grouping by index
    Answer: a. Rotating and summarizing data dimensionsowox​
48. What type of aggregation is commonly used for comparison of sales by region and year?
    a. Multi-dimensional (spatial + time)
    b. Manual aggregation
    c. Boolean aggregation
    d. Data duplication
    Answer: a. Multi-dimensional (spatial + time)coresignal+1​
49. Which language and tool is most popular for aggregation in data science?
    a. Python with pandas
    b. C++ with OpenCV
    c. Java with Spring
    d. Ruby with Rails
    Answer: a. Python with pandasdatawars​
50. Summing up numerical column values in a dataset is called:
    a. Aggregation using SUM()
    b. Filtering
    c. Merging
    d. Grouping
    Answer: a. Aggregation using SUM()w3schools+2​

1. https://www.geeksforgeeks.org/sql/aggregate-functions-in-sql/
2. https://www.dremio.com/wiki/aggregate-functions/
3. https://www.w3schools.com/sql/sql_aggregate_functions.asp
4. https://www.sentinelone.com/cybersecurity-101/data-and-ai/what-is-data-aggregation/
5. https://coresignal.com/blog/data-aggregation/
6. https://www.geeksforgeeks.org/data-analysis/aggregation-in-data-mining/
7. https://www.sanfoundry.com/sqlserver-mcqs-aggregation-data/
8. https://www.scribd.com/document/349651688/Aggregate-Functions-Questions-and-Answers
9. https://www.owox.com/blog/articles/data-aggregation-techniques-for-effective-data-analysis
10. https://www.secoda.co/learn/understanding-sql-functions-and-aggregations
11. https://www.datawars.io/data-science-project/4cd95998-pandas-grouping-and-aggregation-mcq-challenge
12. https://testbook.com/objective-questions/mcq-on-aggregate-functions–5eea6a0939140f30f369da92
13. https://www.sanfoundry.com/1000-data-science-questions-answers/
14. https://www.gyansetu.in/blog/data-science-objective-type-mcq-quiz-interview-preparation/
15. https://www.interviewbit.com/data-science-mcq/
16. https://www.orbitanalytics.com/glossary/data-aggregation/
17. https://interviewkickstart.com/blogs/articles/data-science-mcq-answers
18. https://www.scribd.com/document/705848941/Data-Science-MCQ-Questions-and-Answer-PDF
19. https://www.placementpreparation.io/mcq/data-science/
20. https://learn.microsoft.com/en-us/dax/aggregation-functions-dax