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Overall MCQs for Reference
- What is duplicate data in data science?
a. Multiple identical records
b. Missing entries
c. Irrelevant columns
d. Outlier values
Answer: a. Multiple identical recordssciencedirect - Which of the following is the main consequence of duplicate data?
a. Improved accuracy
b. Loss of data integrity
c. Faster processing
d. Better visualization
Answer: b. Loss of data integrityexamveda - What term describes storing the same data in more than one location?
a. Data normalization
b. Data redundancy
c. Data validation
d. Data sampling
Answer: b. Data redundancyaskfilo - How are duplicate records usually detected?
a. Random sampling
b. Unique identifiers
c. Aggregation
d. Correlation
Answer: b. Unique identifiersnumerous - Which function in Pandas helps to remove duplicates?
a. drop_duplicates()
b. remove_duplicates()
c. clean_duplicates()
d. delete_duplicates()
Answer: a. drop_duplicates()placementpreparation - What is “deduplication” in data cleaning?
a. Sorting data
b. Removing duplicate records
c. Converting data formats
d. Filtering outliers
Answer: b. Removing duplicate recordskaggle - Which of the following is a drawback of duplicate data in analysis?
a. Faster results
b. Distorted analytics
c. Reduced memory usage
d. Clearer visualization
Answer: b. Distorted analyticsnumerous - In databases, what is a potential cause of duplicate data?
a. Lack of normalization
b. Frequent backups
c. Encryption errors
d. Transaction logging
Answer: a. Lack of normalizationsciencedirect - Which data cleaning step specifically addresses duplicate entries?
a. Standardize data formats
b. Remove irrelevant columns
c. Remove duplicate observations
d. Handle missing data
Answer: c. Remove duplicate observationstableau - What data issue is introduced by importing multiple datasets with overlapping records?
a. Missing data
b. Duplicate entries
c. Data normalization
d. Feature scaling
Answer: b. Duplicate entriesnumerous - Which technique helps to detect near-duplicate records?
a. Exact string matching
b. Fuzzy matching
c. Encryption
d. Data partitioning
Answer: b. Fuzzy matchingimprovado - What is an effect of storing duplicate data on disk?
a. Increases storage costs
b. Decreases processing time
c. Improves data accuracy
d. Reduces data size
Answer: a. Increases storage costsijraset - What impact does duplicate data have on machine learning models?
a. Higher accuracy
b. Lower accuracy
c. Shorter training time
d. No impact
Answer: b. Lower accuracydagshub - Deduplication is most effective when it is performed:
a. Before analysis
b. After visualization
c. During model evaluation
d. After reporting
Answer: a. Before analysiskaggle - In Pandas, which method identifies duplicate rows?
a. duplicated()
b. drop_missing()
c. find_duplicates()
d. copy()
Answer: a. duplicated()saidatascience - Which attribute can be used to uniquely identify a record?
a. Timestamp
b. Unique identifier (ID)
c. Data type
d. Value count
Answer: b. Unique identifier (ID)alation - What is a recommended action when duplicates are found in marketing data?
a. Ignore them
b. Merge contact records
c. Delete all data
d. Increase dataset size
Answer: b. Merge contact recordsimprovado - What is the effect of unchecked duplicate questions in MCQ repositories?
a. Increases repository value
b. Reduces content quality
c. Improves test fairness
d. Enhances coverage
Answer: b. Reduces content qualityceur-ws - Which algorithm is commonly used for deduplication in databases?
a. Clustering
b. Decision tree
c. Regression
d. Feature scaling
Answer: a. Clusteringijraset - Duplicate data can arise from which of the following sources?
a. Human error
b. Automated data imports
c. System integrations
d. All of the above
Answer: d. All of the abovenumerous - What kind of matching does advanced deduplication involve?
a. Only exact matching
b. Exact and fuzzy matching
c. Only fuzzy matching
d. Random matching
Answer: b. Exact and fuzzy matchingimprovado - Which metric is important for evaluating deduplication systems?
a. Recall
b. Variance
c. Skewness
d. Kurtosis
Answer: a. Recallijraset - What problem can duplicate records cause in data visualization?
a. Clearer charts
b. Misleading results
c. Improved structure
d. Reduced sample size
Answer: b. Misleading resultsnumerous - In large datasets, duplicate detection is known as:
a. Entity Resolution
b. Data Transformation
c. Data Encryption
d. Data Sampling
Answer: a. Entity Resolutionceur-ws - Which best practice ensures prevention of future duplicates?
a. Data validation at entry
b. Frequent backups
c. Outlier removal
d. Aggregation
Answer: a. Data validation at entryalation - Deduplication using NLP involves:
a. Parsing only numeric fields
b. Comparing semantic similarity
c. Encrypting data
d. Sorting by timestamps
Answer: b. Comparing semantic similarityceur-ws - What is the recommended way to merge duplicates?
a. Keep the most recent record
b. Keep all records
c. Delete all records
d. Randomly select
Answer: a. Keep the most recent recordimprovado - What type of analysis can be distorted by duplicate records?
a. Regression
b. All types of analysis
c. Dimension reduction only
d. Visualization only
Answer: b. All types of analysisnumerous - Deduplication accuracy can be measured with:
a. ROC curve
b. Z-score
c. Confidence interval
d. R-squared
Answer: a. ROC curveijraset - When cleaning marketing data, which field combination helps detect duplicates?
a. Name and address
b. Country and continent
c. Time and date
d. Sales and revenue
Answer: a. Name and addressimprovado - What does maintaining a unique identifier in a dataset prevent?
a. Duplicate records
b. Missing data
c. Outliers
d. Irrelevant fields
Answer: a. Duplicate recordsalation - Which data quality issue arises from duplicate entries?
a. Lack of accuracy
b. Improved precision
c. More clarity
d. Increased memory space
Answer: a. Lack of accuracydagshub - Machine learning for duplicate detection uses:
a. Pattern recognition
b. Clustering algorithms
c. NLP
d. All of the above
Answer: d. All of the aboveijraset - Storage optimization systems use deduplication to:
a. Reduce redundancy
b. Increase duplicates
c. Add missing values
d. Randomize data
Answer: a. Reduce redundancyijraset - In entity resolution, “near-duplicates” refer to:
a. Slightly different records
b. Completely identical entries
c. Irrelevant columns
d. Outlier transactions
Answer: a. Slightly different recordsceur-ws - Which process checks data for duplicates before entry?
a. Real-time validation
b. Aggregation
c. Indexing
d. Normalization
Answer: a. Real-time validationijraset - How can duplicates affect pharmacovigilance reporting?
a. Reduce underreporting
b. Increase confusion and costs
c. No effect
d. Accelerate automation
Answer: b. Increase confusion and costspmc.ncbi.nlm.nih - What is the first step in a systematic data cleansing process?
a. Data validation and profiling
b. Outlier removal
c. Imputation
d. Transformation
Answer: a. Data validation and profilingimprovado - What combination of algorithms is effective for duplicate detection?
a. Supervised and unsupervised learning
b. Only unsupervised learning
c. Only supervised learning
d. Regression and classification
Answer: a. Supervised and unsupervised learningijraset - Duplicate data can negatively affect:
a. Data integrity
b. Storage efficiency
c. Analytics
d. All of the above
Answer: d. All of the aboveexamveda+1 - What kind of tool is essential for large-scale deduplication in data repositories?
a. Automation tools
b. Manual review tools
c. Visualization software
d. Random sampling tools
Answer: a. Automation toolsnumerous - Data deduplication is vital for:
a. Modern storage systems
b. Small, static datasets
c. Visualization only
d. Data encryption
Answer: a. Modern storage systemsijraset - What is a real-world example of duplicate data affecting results?
a. Identical customer profiles in CRM
b. Unique entries in logs
c. Random outlier detection
d. Merged addresses in one record
Answer: a. Identical customer profiles in CRMnumerous - Which of the following can create duplicates in big data systems?
a. System integrations
b. Automated imports
c. Human error
d. All of the above
Answer: d. All of the abovenumerous - What does preprocessing for duplicate data involve?
a. Initial data scan for duplicates
b. Visualization setup
c. Model deployment
d. Algorithm selection
Answer: a. Initial data scan for duplicatesceur-ws - What value does deduplication add to data quality?
a. Increases reliability
b. Distorts analysis
c. Reduces storage
d. Improves model performance
Answer: a. Increases reliabilitydagshub+1 - What technique can help in identifying near-duplicates in text fields?
a. NLP-based similarity
b. Sorting algorithms
c. Outlier analysis
d. Data normalization
Answer: a. NLP-based similarityceur-ws - What is necessary for de-duplication in AI applications?
a. Consistency checks
b. Unique identifiers
c. Automated alerts
d. All of the above
Answer: d. All of the aboveijraset - Which field is often profiled first for duplicate detection?
a. Transaction ID
b. Data type
c. Value range
d. Outlier percentage
Answer: a. Transaction IDimprovado - What is a major future challenge for duplicate detection systems?
a. Handling increasing data volumes
b. Reducing system integrations
c. Minimizing sample size
d. Improving encryption methods
Answer: a. Handling increasing data volumessciencedirect+1esalation+1
- https://www.sciencedirect.com/topics/computer-science/duplicate-detection
- https://www.examveda.com/duplicate-data-often-results-in-loss-of-data-integrity-because-24368/
- https://askfilo.com/user-question-answers-smart-solutions/multiple-choice-questions-mcq-1-the-duplication-of-data-is-3336343034353139
- https://numerous.ai/blog/data-cleaning-techniques
- https://www.placementpreparation.io/mcq/data-science/
- https://www.kaggle.com/code/rtatman/data-cleaning-challenge-deduplication
- https://www.tableau.com/learn/articles/what-is-data-cleaning
- https://improvado.io/blog/marketing-data-cleansing-best-practices
- https://www.ijraset.com/research-paper/ai-ml-based-data-duplication-alert-system
- https://dagshub.com/blog/mastering-duplicate-data-management-in-machine-learning-for-optimal-model-performance/
- https://saidatascience.com/data-handling-and-preprocessing/
- https://www.alation.com/blog/data-cleansing-ai-best-practices-guide/
- https://ceur-ws.org/Vol-3643/paper4.pdf
- https://pmc.ncbi.nlm.nih.gov/articles/PMC12534834/
- https://www.sanfoundry.com/1000-data-science-questions-answers/
- https://www.gyansetu.in/blog/data-science-objective-type-mcq-quiz-interview-preparation/
- https://www.interviewbit.com/data-science-mcq/
- https://www.sanfoundry.com/data-science-questions-answers-introduction-reproducible-research/
- https://arxiv.org/html/2410.03545v1
- https://www.scribd.com/document/856379688/Data-Science-100-MCQs