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Top 25 ML Interview Questions with Answers - Latest Cheat Sheet

Top 25 ML Interview Questions with Answers - Latest Cheat Sheet

By Upskill Campus
Published Date:   5th December, 2024 Uploaded By:    Priyanka Yadav

Prepare confidently for your next machine learning (ML) interview with our comprehensive guide on the top 25 ML Interview Questions and Answers. This blog covers essential ML concepts, techniques, and practical applications, providing concise and updated answers to common questions. Whether you're a fresher or an experienced professional, this cheat sheet ensures you're well-equipped to tackle technical interviews. From supervised learning to neural networks, it’s your go-to resource for mastering key topics and impressing recruiters.

 

Why is it Necessary to Prepare Machine Learning Questions?

 

Companies use smart technologies like artificial intelligence (AI) and machine learning to make our lives easier. These technologies are used in many industries, such as banking, finance, and healthcare. For example, AI can help banks detect fraud, while machine learning can help doctors diagnose diseases more accurately.
 

Suppose you're interested in a job in data science, AI engineering, machine learning engineering, or data analysis. In that case, it's important to be prepared for the kinds of machine learning interview questions and answers you might be asked. These questions will test your knowledge and skills in these areas.

 

Top 25 ML Interview Questions With Answers

 

Machine learning engineers are very important for many businesses. They help companies grow and improve customer satisfaction. If you're looking for a job as a machine learning engineer or hiring one, this section has 25 machine learning questions and answers to help you prepare for or conduct interviews.

 

1. What are the Various Types of Machine Learning?

 

There are three main types of machine learning:
 

  • Supervised Learning: In this type, the computer learns from labeled data. This means the data is already tagged or categorized, and the computer learns to recognize patterns and make predictions based on these labels. For example, a computer could learn to classify emails as spam or not spam based on a dataset of labeled emails.
     
  • Unsupervised Learning: Here, the computer learns from unlabeled data. It finds patterns and relationships within the data on its own, without any prior guidance. For example, a computer could group customers into different segments based on their purchasing behavior.
     
  • Reinforcement Learning: In this type, the computer learns by trial and error. It takes actions and receives rewards or penalties based on the outcomes. Over time, it learns to make decisions that maximize rewards and minimize penalties. For example, a robot could learn to navigate a maze by trying different paths and receiving rewards for reaching the goal and penalties for hitting obstacles.

 

2. Explain Overfitting - How to Avoid It?

 

Overfitting happens when a model learns the training data too well, so it doesn't work well on new data. In other words, it memorizes a test too well but does not understand the concepts.

To avoid overfitting, we can:
 

  • Simplify the model: Use fewer variables and parameters.
  • Regularization: Add a penalty to the model's complexity.
  • Cross-validation: Test the model on different parts of the data.
  • LASSO regularization: Penalize specific model parameters that might cause overfitting.

The above inquiries will help you to prepare ML interview questions.

 

3. How Will You Handle Missing or Corrupted Data in a Dataset?

 

Missing or corrupted data can be a problem in machine learning. Here are some ways to deal with it:
 

Dropping Data:

  • Remove rows: If a row has missing values, you can remove the entire row.
  • Remove columns: If a column has many missing values, you can remove the entire column.


Filling Missing Values:

  • Mean/Median/Mode Imputation: Replace missing values with the mean, median, or mode of the column.
  • Interpolation: Use interpolation techniques to estimate missing values based on neighboring values.
  • Constant Value Imputation: Replace missing values with a fixed value, like 0 or -1.

Pandas, a popular Python library for data analysis, provides functions like isnull(), dropna(), and fillna() to help you handle missing data effectively.

 

4. What is Logistic Regression?

 

Logistic regression is a type of math that helps us make yes-or-no decisions. Moreover, we give it information, and it predicts whether the answer is yes (1) or no (0). For example, we could give it information about a person's age, income, and whether they have a job. The logistic regression model could then predict whether that person is likely to buy a certain product.
 

It works by assigning a number to each piece of information. If the total number is above a certain threshold (usually 0.5), the prediction is "yes." If it's below, the prediction is "no."

 

5. Explain Pruning in Decision Trees, and What is Working.

 

A decision tree is a flowchart. Pruning is like trimming unnecessary branches from this tree. By removing unnecessary parts, we can make the tree simpler and more accurate.
 

There are two main ways to prune:

  • Top-down Pruning: Start at the top of the tree and remove branches that aren't helpful.
  • Bottom-up Pruning: Start at the bottom of the tree and remove branches that don't add much value.


One common method is called Reduced Error Pruning. It works by replacing branches with the most common outcome. If this doesn't hurt the accuracy, the change is kept. Pruning helps to prevent overfitting, where the tree becomes too complex and starts to memorize the training data instead of learning general patterns. These are the most commonly asked ML interview questions. Further, we’ll discuss the other one. 

 

6. Explain Briefly the Decision Tree Classification

 

A decision tree is a flowchart. It starts with a main question, and based on the answer, it splits into smaller questions. However, this process continues until we reach a final decision.

Decision trees can be used to classify things (like whether an email is spam or not) or to predict numbers (like how much a house will cost). Moreover, they can work with different types of data, like text or numbers.

 

7. What is Precision and Recall?

 

Precision and recall are two important metrics used to evaluate the performance of classification models. Moreover, they help us understand how well a model can correctly identify positive instances.

  • Precision measures how accurate the positive predictions are. In addition, it's the ratio of true positive predictions to the total number of positive predictions made by the model.
  • Recall measures how well the model can identify all positive instances. It's the ratio of true positive predictions to the total number of actual positive instances.

A high precision indicates that the model makes accurate positive predictions, while a high recall indicates that the model is identifying most of the positive instances. 

 

8. Explain the Trade-off Between Variance and Bias. 

 

After understanding the basics of machine learning coding interview questions, we’re proceeding further. Imagine you're trying to predict house prices. You have a simple model that only considers the size of the house. This model might be biased, meaning it consistently underestimates or overestimates prices. However, it has low variance, meaning it gives similar predictions for different datasets.
 

On the other hand, you could have a complex model that considers many factors like location, age, number of rooms, etc. Moreover, this model might be more accurate on average (low bias), but it can be inconsistent (high variance), meaning its predictions can vary widely depending on the specific dataset.
 

The goal is to find a balance between bias and variance. A model that's too simple will be biased, and a model that's too complex will be too sensitive to noise in the data.

 

9. What is the K Nearest Neighbor Algorithm?

 

The K-Nearest Neighbors (KNN) algorithm is a simple way to figure this out. You compare your new ball to other balls you already know the type of. You find the K most similar balls, and then you choose the type that the majority of these K balls belong to.

For example, if you choose K=3, you'll find the 3 balls that are most similar to your new ball. If 2 of these 3 balls are basketballs and 1 is a football, then the KNN algorithm would predict that your new ball is most likely a basketball.

 

10. Explain Recommendation System

 

Suppose you're on Spotify and you just listened to a new song you really liked. Spotify then suggests other songs you might enjoy. Or, on Amazon, after buying a book, you're shown similar books you might like. Therefore, this is a recommendation system. It's a smart assistant that learns your preferences and suggests things you'll enjoy.

 

11. Briefly Describe Kernel SVM.

 

This is one of the common interview questions for machine learning. 

Kernel SVM is a smart technique that can do this, even if the groups aren't easily separable. However, it works by transforming the data into a higher-dimensional space, where the groups become more distinct and easier to separate.

 

12. What are Diverse Approaches for Reducing Dimensionality?

 

You can simplify your data by combining features, removing unnecessary ones, or using special techniques to reduce the number of dimensions. Now that you've practiced these machine learning interview cheat sheets, you should better understand your strengths and weaknesses in this field.

 

13. Explain the Principal Component Analysis

 

PCA is a tool that can simplify this data. It combines the most important parts of the data into a smaller, easier-to-understand form. However, this helps you see the big picture and find important patterns that keep you from getting lost in all the details.

 

14. Briefly Explain F1 Score
 

The F1 score is a measure of how well this model performs. Moreover, it combines two important metrics: precision and recall. A high F1 score means the model is both accurate (predicting correctly) and comprehensive (finding all the spam emails). The F1 score is calculated based on the precision and recall values. A perfect F1 score of 1 indicates that the model is highly precise and comprehensive. The above inquiries will help you to prepare ML interview questions.

 

15. Explain Type I and Type II Error.
 

Type I Error: This happens when the null hypothesis is correct and we reject it.

Type II Error: This happens when a null hypothesis is false and we accept it.

 

16. What do you mean by Correlation and Covariance?


Correlation tells us how much these two things are related. If taller people tend to be heavier, they are positively correlated. If taller people tend to be lighter, they are negatively correlated.

On the other hand, Covariance is similar, but it tells us the direction of the relationship without telling us how strong it is. A positive covariance means that as one variable increases, the other tends to increase too. Moreover, a negative covariance means that as one variable increases, the other tends to decrease.

 

17. Explain Support Vectors in SVM.


You draw a line to divide them. The people closest to the line are the support vectors. They're the most important people in determining where the line should be drawn. If you remove these people, the line might move to a different position. Moreover, these support vectors are crucial in building a support vector machine (SVM) model.

 

18. Briefly Describe Ensemble Learning


The upcoming section will assist you in preparing for machine learning interview questions in a better way. 

Suppose you're trying to predict the weather. Instead of relying on just one weather forecast, you ask 100 different experts. By combining all their predictions, you can get a more accurate forecast than relying on just one. However, this is similar to ensemble learning. It combines the results from many different models to get a more accurate and reliable prediction.

 

19. What do you mean by Cross-Validation?


Cross-validation helps us test a machine-learning model on different parts of the data to make sure it performs well on new, unseen data.
 

20. How does the Support Vector Machine (SVM) Algorithm Effectively Manage self-learning?
 

The learning rate is like the size of the reward or punishment. A high learning rate means the object learns quickly, but it might make mistakes. Moreover, a low learning rate means the object learns slowly but more accurately. The expansion rate is to find the best way to fetch the ball. A good expansion rate helps the object find the shortest path to the ball.


21. What are the 5 Primary Assumptions You Should Take Before Initiating Linear Regression?


The five assumptions that you should take before starting with linear regression are as follows: 

  • Multivariate normality
  • Homoscedasticity
  • No auto-correlation
  • No or little multicollinearity
  • Linear relationship

This is one of the common machine learning engineer interview questions. 


22. Explain Semi-supervised Machine Learning


Imagine you're teaching a child to identify different animals. You can't label every single animal, but you can show them a few labeled examples (like a dog and a cat). The child can then use these examples to group similar animals (like other dogs and cats). However, this is similar to semi-supervised learning. It uses a small amount of labeled data to train a model, which then uses that knowledge to classify unlabeled data. Moreover, this technique is useful when labeling a large dataset is expensive or time-consuming.


23. Why do computer vision models often require significant computational resources? Explain with an example.


The following section will discuss the important ML engineer interview questions. 

When you use a neural network to process this image, it needs to consider all these pixels. This can lead to a very large number of calculations. To make things easier, we use a technique called convolution. This technique helps the neural network focus on smaller parts of the image at a time, making the calculations more efficient.


24. Explain Syntactic Analysis.


Syntactic analysis is like understanding the grammar of a sentence. It helps us figure out how words are connected and how they form a complete sentence. By analyzing the grammar, we can better understand the meaning of the sentence.

After understanding all the concepts, you can effortlessly practice ML interview questions with answers. 


25. Briefly Explain the Hypothesis in Machine Learning.


A hypothesis is a guess about how these factors influence the price of the house. It's a formula that tries to predict the price based on the input information.

 

Conclusion

 

To sum up, ML interview questions cover a lot of ground, from basic ideas to complex methods. However, it's important to know about core algorithms like linear regression and decision trees. You should also be familiar with techniques like improving your data and fine-tuning your models. As machine learning keeps growing, it's crucial to stay up-to-date with the latest developments.

 

Frequently Asked Questions

 
Q1. Are machine learning and deep learning the same?

Ans. Machine learning and deep learning are related but not the same. Deep learning is a specific type of machine learning that uses artificial neural networks to learn complex patterns from data. While all deep learning is machine learning, not all machine learning is deep learning.


Q2. How to get a job as a machine learning engineer?

Ans. While a machine learning engineer job can be very lucrative, it's usually easier to get one if you've completed a course or certification program.

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UpskillCampus provides career assistance facilities not only with their courses but with their applications from Salary builder to Career assistance, they also help School students with what an individual needs to opt for a better career.

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