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50+ Machine Learning Interview Questions

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Machine Learning interview questions will assess your interest in the subject. You can ace any Machine Learning system design interview at various technical and FAANG+ companies if you are passionate about the subject.

Machine Learning entails resolving real-world issues. Machine learning algorithms learn from data, as opposed to using a hard coding rule to solve a problem. Around 82% of the companies are using Machine Learning and AI to get the most out of their investments. As a result, the need for expert machine learners has skyrocketed.

Learn how to prepare for a Machine Learning interview by reading some of the most often asked Machine Learning engineer interview questions.

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Here's what we'll discuss in this article:

  • How to Prepare for a Machine Learning Interview?
  • Machine Learning Interview Questions on Programming Skills 
  • Machine Learning Interview Questions on Algorithms and Theory
  • Machine Learning Interview Questions on General Interest 
  • Sample Machine Learning Interview Questions for Practice
  • FAQs on Machine Learning Interview Questions 

How to Prepare for a Machine Learning Interview?

If you are looking for how to prepare for Machine Learning interviews, you must grasp in-depth knowledge about the subject. Machine Learning Engineer interview questions are asked in the following four aspects:

  • Machine Learning - Probability, statistics, linear algebra, decision trees, and many more
  • Deep Learning - All about neural networks
  • Software - Algorithms and data structures
  • Domain Expertise - Vision, NLP, speech, compression, quantization, finance, hardware, computer architecture, and others

You should prepare from books at the initial stages. You must know the fundamentals of machine learning, its terminologies, and its scope to represent yourself as the right fit in your machine learning system design interview. 

You should mention experiences briefly concerning machine learning. Technical companies look for experienced and knowledgeable machine learning engineers. You should read the job description carefully and prepare a list of key roles they are looking for. If they are looking for a system design machine learning engineer, you can expect behavioral and situational questions in your interview. 

Additionally, to crack any interview in the first attempt, you must prepare Machine Learning Engineer interview questions and learn how to answer them professionally. Below are 50+ Machine Learning interview questions that you can practice to let your interviewer know you are the right person for their company. 

Recommended Reading: Machine Learning vs. Data Science — Which Has a Better Future? 

You must rehearse Machine Learning Engineer interview questions beforehand. You must practice them in speech and learn how to answer them professionally. Here are a few Machine Learning Engineer interview questions based on programming skills, algorithms, and companies. 

Machine Learning Interview Questions on Programming Skills 

Q1. How do you handle corrupted or missing data in a dataset?

You could find corrupted or missing data in a dataset by either dropping those rows or columns or replacing them with another value. There are two methods - isnull() and dropna(). These methods will help you find columns of missing/corrupted data. If you want to fill invalid values with a placeholder value, you could use the fillna() method. 

Q2. Do you know what Spark is? Do you have any experience using it?

This is one of the commonly asked Machine Learning interview questions that test your knowledge and experience in Spark. A spark is a great tool used to handle massive datasets with speed. It is presently in demand. So, you must have sufficient knowledge and experience using it if you want to nail your machine learning interview. 

Q3. What is the difference between a list and an array? 

The differences between a list and an array are:

Q4. What is a hash table?

A hash table is a data structure that produces an associative array. A hash table is used for database indexing. In a hash table, a key is mapped to certain values through a hash function. 

Q5. How are foreign and primary keys related to SQL?

If you are attempting Machine Learning interview questions at top-ranked technical or FAANG companies, you must have a profound knowledge of various data formats. SQL is one of those. You should be familiar with how to manipulate SQL databases. The key differences between a primary and foreign key are:

Q6. What are data types supported by JSON?

You must be adept in JSON to answer these types of Machine Learning interview questions. You can manipulate six data types in JSON - numbers, strings, objects, null values, arrays, and booleans. 

Learn some tips on Google Machine Learning Engineer Interview Prep here.

Machine Learning Interview Questions on Algorithms and Theory

Q1. What is the difference between bias and variance?

Bias is an error that occurs due to overly simplistic assumptions or erroneous assumptions in the learning algorithm. If you use bias, it can lead to the model underfitting your data with low predictive accuracy. 

On the other hand, variance is an error due to complexity in the learning algorithm. In variance, your data gets highly sensitive to high degrees of variation, leading your model to overfit the data. You'll end up carrying noise from your training data for your model to be useful for your test data. 

Q2. How will you differentiate between supervised and unsupervised machine learning?

Supervised learning required training labeled data. For instance, to classify a supervised learning task, you must first label the data you'll use to train the model. Contrastingly, unsupervised learning does not require labeling data explicitly. 

Q3. How does a ROC curve work? 

ROC is a graphical representation of the contrast between true positive rates and the false positive rate at various thresholds. You should know that it's often used as a proxy for the trade-off between the true positives (sensitivity of the model) vs. the false positives (fall-out or probability to trigger a false alarm). 

Q4. What is Bayes' theorem? How is it useful in machine learning?

To answer Machine Learning interview questions based on Bayes' theorem, you must have clear concepts on such mathematical topics. Using Bayes' theorem, you can get the posterior probability of an event given that is known as prior knowledge. Bayes' theorem notably includes the Naive Bayes classifier. 

Q5. What is 'Naive' Bayes naive?

Naive Bayes is considered naive because it makes assumptions impossible to see in real-life data. Despite its practical applications, especially in text mining, the resulting probability implies the absolute independence of features, which is a condition that can never be met in real life. 

Q6. What is the difference between L1 and L2 regularization?

L1 is binary/sparse, with many variables assigned a 1 or 0 in weighting. It corresponds to setting a Laplacean before the terms. In contrast, L2 regularization tends to spread error among all the terms. L2 corresponds to a Gaussian prior. 

Q7. What is deep learning? How does it contrast with other machine learning algorithms?

You must be well-versed in deep learning to answer these types of Machine Learning interview questions. Deep learning is a subset of machine learning. It is concerned with neural networks to perform the following operations:

  1. How to use backpropagation and certain principles
  2. How to accurately model large sets of semi-structured and unlabelled data

It represents an unsupervised learning algorithm that learns data representations through the use of neural networks. 

Nail Apple’s Machine Learning Engineer Interview. Know what and how to prepare.

Machine Learning Interview Questions on General Interest 

Q1. Do you have research experience in machine learning?

You must know that various top technical and FAANG companies look for experienced machine learning engineers. So, while answering these types of Machine Learning interview questions, you must highlight your experiences to make a difference in your hiring process. You can tell them about the research papers co-authored or supervised by leaders in the field. 

Q2. What are your favorite use cases of machine learning models?

These types of questions are asked to test your deep knowledge about machine learning in an interview. Make sure to have a few examples in mind and describe what resonated with you. You must demonstrate an interest in how machine learning is implemented. 

Q3. Where do you usually source datasets?

These are the most asked Machine Learning interview questions. You should be passionate about machine learning to answer such questions. Answering these questions will strongly impact the interviewer at any FAANG or top technology company. You must have adequate knowledge about datasets and which one is great. 

Q4. What are your favorite APIs to explore?

You need to have clear concepts on APIs to answer these types of Machine Learning interview questions. If you have worked with external data sources, it will be easier to answer these questions. You can mention the kinds of experiments and pipelines you have run in the past. You can also mention how APIs' usage has transformed over the past years. 

Q5. How do you think quantum computing will affect machine learning?

These types of Machine Learning interview questions test your interest in quantum computing. You must answer these questions concerning the present-day scenarios and how this new format and way of thinking will change the future. You must demonstrate your knowledge in this area to show your keen interest in machine learning at a higher level. 

Sample Machine Learning Interview Questions for Practice

Here are a few sample Machine Learning interview questions for your practice: 

  1. What are the different types of machine learning?
  2. What is overfitting, and how to avoid it?
  3. What are the “training Set” and “test Set” in a Machine Learning Model? How much data will you allocate for your training, validation, and test sets?
  4. Explain the confusion matrix with respect to machine learning algorithms.
  5. Write a pseudo code for a parallel implementation. 
  6. What data visualization tools do you use?
  7. What are the three stages of building a model in machine learning?
  8. Given two strings, A and B, of the same length n, find whether it is possible to cut both strings at a common point such that the first part of A and the second part of B form a palindrome.
  9. How do XML and CSVs compare in terms of size?
  10. What is the difference between inductive machine learning and deductive machine learning? 
  11. How would you build a data pipeline?
  12. How is KNN different from k-means clustering?
  13. What is PCA? When do you use it?
  14. Will you explain your favorite algorithm in less than a minute?
  15. What are type I and II errors?
  16. What is a Fourier transform?
  17. What is the difference between probability and likelihood?
  18. What is an F1 score? How will you use it?
  19. Explain the SVM algorithm in detail.
  20. Which one is more important - model performance or model accuracy?
  21. How is a decision tree pruned?
  22. What is the difference between generative and discriminative models?
  23. How will you handle an imbalanced dataset?
  24. How do you ensure you're not overfitting with a model?
  25. What is a kernel trick? How is it useful?
  26. What do you think of the current data process?
  27. How can you use machine learning skills to generate revenue?
  28. How would you implement a recommendation system for our company's users?
  29. What do you think is the most valuable data in our business?
  30. How will you approach the Netflix Prize competition?
  31. How do you think Google is training data for self-driving cars?
  32. How would you simulate the approach AlphaGo took to beat Lee Sedol at Go?
  33. What are your thoughts on GPT-3 and OpenAI's model?
  34. How do you design an email spam filter?
  35. What models do you train for fun, and what GPU/hardware do you use?

Learn about the Amazon Machine Learning Engineer Interview Process here.

FAQs on Machine Learning Interview Questions 

Q1. How do I prepare for Machine Learning interview questions?

To prepare for a Machine Learning system design interview, you must practice questions based on your skills in computer science fundamentals, machine learning algorithms, applications of these algorithms, and other related topics. You must also be adept in deep learning software engineering and answer questions related to compression, quantization, finance, hardware, and others. 

Q2. Are machine learning interview questions easy?

Machine Learning interview questions vary from company to company and the type of job profile. However, they are easy to answer if you know about the basics of machine learning. So, to ace your machine learning interview, you must acquire vast knowledge about the subject and its advantages/disadvantages. 

Q3. What do Machine Learning interview questions look like?

If you are preparing for a machine learning interview, you can expect technical coding and questions like encoding a tweet or going through a log of processes. The technical part is to test your intuition for machine learning theory. Besides this, you can expect situational questions as a part of Machine Learning interview questions. 

Ace Your Machine Learning Interview 

If you need help with your prep, join Interview Kickstart’s Machine Learning Interview Course — the first-of-its-kind, domain-specific tech interview prep program designed and taught by FAANG+ instructors. Click here to learn more about the program. 

IK is the gold standard in tech interview prep. Our programs include a comprehensive curriculum, unmatched teaching methods, FAANG+ instructors, and career coaching to help you nail your next tech interview. 

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