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2103 Curated Machine Learning, Data Science, AI & LLMs Interview Questions
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Top 83 Data Processing Interview Questions

Entry Junior Mid Senior Expert
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Data Processing Theoretical Questions

Q1:   

What is Data Preprocessing? What preprocessing steps do you know?

  
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Q2:   

What is the difference between Data Processing and Data Mining?

  Related To: Data Mining
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Q3:   

What is Data Binning?

  
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Q4:   

What's the difference between Feature Engineering vs. Feature Selection?

  Related To: Feature Engineering
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Q5:   

What is the Importance of Data Reduction?

  
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Q6:   

What is the difference between Feature Selection and Feature Extraction?

  
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Q7:   

What is Cross-Validation and why is it important in supervised learning?

  Related To: Supervised Learning
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Q8:   

Explain how do you understand Dimensionality Reduction

  Related To: Dimensionality Reduction
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Q9:   

Would you use K-NN for large datasets?

  Related To: K-Nearest Neighbors
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Q10:   

Should your Test Data be Cleaned the same way that the Training Data is?

  
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Q11:   

How can less Training Data give Higher Accuracy?

  Related To: SVM
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Q12:   

What is the difference between Normalization and Scaling?

  
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Q13:   

Name some benefits of Feature Selection

  Related To: Feature Engineering
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Q14:   

What's the difference between Covariance and Correlation?

  Related To: Linear Regression
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Q15:   

Why is data more sparse in a high-dimensional space?

  Related To: Curse of Dimensionality, Dimensionality Reduction
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Q16:   

Name some methods you know for Rebalancing a dataset using Rebalancing Design Pattern

  Related To: ML Design Patterns
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Q17:   

What is the difference between Non-dependency and Dependency-oriented data?

  
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Q18:   

What are some recommended choices for Imputation Values?

  Related To: ML Design Patterns, Feature Engineering
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Q19:   

How do you encode Categorical Data which consists of both Ordinal and Nominal data types?

  
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Q20:   

How do you choose the Scaling method used for Neural Networks?

  Related To: Neural Networks
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Q21:   

How do you Normalize Real-Time Data?

  
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Q22:   

If you are using k-Nearest Neighbors, what type of Normalization should be used?

  Related To: K-Nearest Neighbors
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Q23:   

Is it a good idea to Clean the Data Automatically?

  
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Q24:   

What Distance Function do you use for Quantitative Data?

  Related To: Cost Function
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Q25:   

What are some common steps in Data Cleaning?

  
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Q26:   

Can you use different Normalization methods on different features?

  
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Q27:   

What is the l1l_1 Normalization of a data?

  
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Q28:   

Explain the two types of Data Reducing Algorithms

  
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Q29:   

How to detect data drift in Azure Machine Learning?

  Related To: Azure ML, MLOps
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Q30:   

When would you use Equal Frequency Binning and when do you use Equal Width Binning?

  
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Q31:   

What are some reasons that data goes Missing?

  
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Q32:   

How do you cope with Missing data in Regression?

  Related To: Linear Regression
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Q33:   

Does Redundant data affect an SVM-based classifier?

  Related To: SVM
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Q34:   

Explain some Encoding techniques for Categorical Data

  
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Q35:   

What's the difference between StratifiedKFold (with shuffle = True) and StratifiedShuffleSplit in Scikit-Learn?

  Related To: Scikit-Learn
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Q36:   

When to use OneHotEncoder vs LabelEncoder in Scikit-Learn?

  Related To: Scikit-Learn
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Q37:   

Are there any problems with splitting data randomly into Training, Validation, and Test datasets?

  Related To: ML Design Patterns
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Q38:   

What are some common practices for Preprocessing data for LLMs?

  Related To: LLMOps, LLMs
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Q39:   

How does K-fold Cross Validation work?

  
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Q40:   

When would you remove Correlated Variables?

  Related To: Feature Engineering
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Q41:   

What is the difference between Test Set and Validation Set?

  Related To: Machine Learning
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Q42:   

What are the assumptions before applying the OLS estimator?

  Related To: Linear Regression
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Q43:   

What are the difference between Type I and Type II errors?

  Related To: Model Evaluation, Machine Learning
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Q44:   

What's the difference between Bagging and Boosting algorithms?

  Related To: Classification, Ensemble Learning, Bias & Variance
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Q45:   

What's the difference between One-vs-Rest and One-vs-One?

  Related To: Classification
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Q46:   

What are some disadvantages of using Decision Trees and how would you solve them?

  Related To: Decision Trees, Ensemble Learning
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Q47:   

Name some best practices for working with Datasets

  
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Q48:   

When you sample, what potential Sampling Biases could you be inflicting?

  Related To: Statistics, Bias & Variance
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Q49:   

How would you determine the needed Sample Size?

  Related To: Statistics
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Q50:   

How to choose the features for a Neural Network?

  Related To: Feature Engineering, Neural Networks
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Q51:   

How can you create a model with a very Unbalanced dataset?

  
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Q52:   

How do you find the Covariance Matrix from Missing Data?

  
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Q53:   

How would you detect Heteroskedasticity?

  Related To: Linear Regression
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Q54:   

When would you use Sequential Split of data?

  Related To: ML Design Patterns, Time Series
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Q55:   

How would you address the problem of Heteroskedasticity caused for a Measurement error?

  Related To: Linear Regression
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Q56:   

How could I (statistically) find features that are more important than others?

  Related To: Statistics
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Q57:   

How would you deal with Outliers in your dataset?

  Related To: Anomaly Detection, Linear Regression
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Q58:   

How would you deal with an Imbalanced Dataset?

  
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Q59:   

What's the difference between Random Oversampling and Random Undersampling and when they can be used?

  Related To: Classification
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Q60:   

How would you use a Confusion Matrix for determining a model performance?

  Related To: Classification, Model Evaluation
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Q61:   

How does the Algorithm "The 10% You Don't Need" remove the Redundant Data?

  Related To: SVM
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Q62:   

Explain what is an Unrepresentative Dataset and how would you diagnose it?

  Related To: Linear Regression
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Q63:   

When you want (and do not want) to scale or standardize a variable prior to model fitting?

  
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Q64:   

What are some approaches to get a quantitative estimate of a model's Maximum Predictive Power given a certain level of noise?

  Related To: Model Evaluation
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Q65:   

Can Data Cleaning worsen the results of Statistical Analysis?

  Related To: Statistics
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Q66:   

What is Multidimensional Scaling?

  Related To: Dimensionality Reduction
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Q67:   

How you can extract useful features from Date and Time column if any?

  
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Q68:   

Is mean imputation of missing data acceptable practice? Why or why not?

  Related To: Statistics
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Q69:   

When would you use chi-Square or an ANOVA test?

  
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Q70:   

How would you handle Missing Data and perform Data Imputation?

  
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Q71:   

Compare Causation vs Correlation

  
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Q72:   

How would you check the Quality of your Dataset?

  
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Q73:   

Which measures of Variability would you use on your data?

  Related To: Statistics
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Q74:   

What are some benefits of Scaling the Data for Neural Networks?

  Related To: Neural Networks
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Q75:   

What are some variations of Cross-Validation?

  
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Q76:   

How do you check if the Missing Data is Missing at Random (MAR) or Not?

  
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Q77:   

How would you normalise Longitude/Latitude feature?

  
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Q78:   

When would you use Fine-Tuning vs Feature Extraction in Transfer Learning?

  Related To: ML Design Patterns, Feature Engineering
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Q79:   

Are there any troubles when using Early Stopping?

  Related To: ML Design Patterns, Model Evaluation, Neural Networks
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Q80:   

How to perform Feature Engineering on Unknown features?

  Related To: Feature Engineering
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Q81:   

How does an ANOVA test work?

  Related To: Statistics
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Q82:   

How does Normalization reduce the Dimensionality of the Data if you project the data to a Unit Sphere?

  Related To: Dimensionality Reduction
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Data Processing Practical Challenges

Q1:   

Between Clean and Noisy data, which one has higher Entropy?

  
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