TOP 50 Machine Learning Interview Questions: A Comprehensive Guide


TOP 50 Machine Learning Interview Questions

TOP 50 Machine Learning Interview Questions: A Comprehensive Guide


In today’s competitive job market, excelling in a machine learning interview is crucial for landing your dream job. This guide provides a comprehensive list of the top 50 machine-learning interview questions to help you prepare effectively.

Table of Contents

TOP 50 Machine Learning Interview Questions A Comprehensive Guide
TOP 50 Machine Learning Interview Questions A Comprehensive Guide

 Q.1) What do you comprehend by machine learning?

Machine learning is a form of artificial intelligence that deals with system programming and automates data analysis to enable computers to learn and act through experiences without being explicitly programmed.

Q. 2) Differentiate between inductive learning and deductive learning.

In inductive learning, the model advances by using models from a bunch of noticed occasions to make a summed-up determination. On the opposite side, in rational learning, the model first applies the end, and afterward the end is drawn.

  • Inductive learning is a strategy for utilizing perceptions to make inferences.
  • Detective learning is the strategy for utilizing ends to frame perceptions.

Q. 3) What is the contrast between data mining and machine learning?

Data mining can be described as the process in which structured data tries to abstract knowledge or interesting, unknown patterns. During this procedure, machine learning algorithms are used.

Machine learning represents the study, design, and development of the algorithms that provide the ability for the processors to learn without being explicitly programmed.

Q. 4) What is the sense of overfitting in machine learning?

Overfitting can be seen in machine learning when a statistical model describes random error or noise instead of the underlying relationship. Overfitting is typically seen when a model is unreasonably perplexing.

It happens because there are too many parameters concerning the number of training data types. The model displays poor performance and has been overfitted.

Q. 5) Why does overfitting occur?

The possibility of overfitting occurs when the criteria used for training the model are not as per the criteria used to judge the efficiency of the model.

Q. 6) What is the method to avoid overfitting?

Overfitting happens when we have a small dataset and a model is attempting to gain from it. Overwhelming information and overfitting can be avoided. Yet, assuming we have a small data set and are compelled to construct a model in light of that, we can utilize a procedure known as cross-approval.

Q. 7) Distinguish between supervised and unsupervised machine learning.

In supervised machine learning, the machine is competent at using labeled data. Then a new dataset is given to the learning model so that the algorithm can provide positive outcomes by analyzing the labeled data.

For example, we first need to label the data, which is necessary to train the model while performing classification.

In supervised machine learning, the machine is not trained using labeled data and lets the algorithms make the decisions without any corresponding output variables. 

Q. 8) How does machine learning differ from deep learning?

Machine learning is all about algorithms that are used to parse data, learn from that data, and then apply whatever they have learned to make informed decisions.

Deep learning is a piece of machine learning that is propelled by the construction of the human mind and is especially helpful in highlighting identification.

Q. 9) How is KNN different from k-means?

KNN, or K closest neighbors, is a directed calculation that is utilized for grouping purposes. In KNN, a test is given as the class of most of its closest neighbors. On the other side, K-means is an unsupervised algorithm that is mainly used for clustering.

In k-means clustering, it only needs a set of unlabeled points and a threshold. The algorithm further takes unlabeled information and figures out how to bunch it into bunches by processing the mean of the distance between various unlabeled focuses.

Q. 10) What are the different types of algorithmic methods in machine learning?

The different types of algorithmic methods in machine learning are:

  1.             Supervised Learning
  2.             Semi-supervised Learning
  3.             Unsupervised Learning
  4.             Transduction
  5.             Reinforcement Learning

Q. 11) What do you understand by the reinforcement learning technique?

Reinforcement learning is an algorithmic technique used in machine learning.

It includes a specialist that interfaces with its current circumstances by creating activities and finding mistakes or rewards. Support learning is utilized by various programs and machines to look for the best reasonable way of behaving or the way it ought to continue in a particular circumstance. It usually learns to bask in the reward or penalty given for every action it performs.

Q. 12) What is the trade-off between bias and variance?

Both bias and variance are errors.

Bias is an error due to inaccurate or excessively simplistic molds in the learning algorithm. It can lead to the model underfitting the data, making it hard to have high predictive accuracy and generalize the knowledge from the training set to the test set.

Variance is a mistake due to the intricacy of the learning calculation. It prompts the calculation to be exceptionally delicate due to the high levels of variety in the preparation information, which can lead the model to overfit the data. 

Q. 13) How do classification and regression differ?

Classification is the task of forecasting a separate class label.Regression is the test of predicting continuous quantity.
In a classification problem, data is considered
to belong to one of two or more classes.
A regression problem needs the forecast of a quantity.
A classification having a problem with two
classes is called binary classification, and more than two classes is called multi-class classification.
A regression issue containing numerous information factors is known as a multivariate relapse issue.
Classifying an email as spam or non-spam is an illustration of a characterization issue.Predicting the price of a stock over time is a regression problem.

Q. 14) What are the five popular algorithms we use in machine learning?

Five popular algorithms are:

  1.             Decision Trees
  2.             Probabilistic Networks
  3.             Neural Networks
  4.             Support Vector Machines
  5.             nearest Neighbor

Q. 15) What do you mean by ensemble learning?

Several models, such as classifiers, are deliberately made and united to solve a particular computational program, which is known as ensemble learning. The ensemble methods are also recognized as committee-based learning or learning multiple classifier systems.

Eurostar has many hypotheses to fix the same issue. One of the most appropriate examples of ensemble modeling is haphazard forest tree trees, where several decision trees are used to predict outcomes. It is used to expand the classification, function approximation, prediction, etc. of a model.

Q. 16) How can we describe model selection in machine learning?

The procedure of selecting models among dissimilar mathematical models, which are used to describe the same data, is known as model selection. Model learning is smeared into the fields of statistics, data mining, and machine learning.

Q. 17) What are the three phases of building the hypotheses or model in machine learning?

There are three phases to building hypotheses or models in machine learning:

  1. Model building

It chooses a suitable algorithm for the model and trains it according to the requirements of the problem.

  1. Applying the model

It is accountable for the examination of the accuracy of the model through the test data.

  1. Model testing

It performs the required changes after testing and applies the final model.

Q. 18) What, to you, is the typical approach to supervised learning?

In supervised learning, the typical approach is to split the set of examples into the training set and the test. 

Q.19) Describe the ‘training set’ and ‘training test’.

In various areas of machine learning information, a set of data is used to discover the potentially predictive relationship, which is known as a ‘Training Set’. The training set is a sample that is given to the beginner.

Besides, the ‘Test set’ is used to test the accuracy of the hypotheses generated by the learner. It is the set of instances held back by the learner. Thus, the training set is dissimilar from the test set.

Q. 20) What are the communal ways to handle missing data in a dataset?

Missing data is one of the standard factors while working with data and handling… There are many ways one can impute the missing values. Some of the common methods to handle missing data in datasets can be defined as deleting the rows, replacing them with mean, median, or mode, predicting the missing values, assigning a unique category, using algorithms that support missing values, etc.

Q. 21) What do you understand by ILP?

ILP stands for inductive logic programming. It is a part of machine learning that uses logic programming. It aims to search for patterns in data that can be used to build predictive models. In this process, the logic programs are assumed to be hypotheses.

Q. 22) What are the necessary steps involved in a machine learning project?

There are numerous vital steps we must follow to achieve a good working model when doing a machine learning project. Those steps may include parameter tuning, data preparation, data collection, training the model, model evaluation, prediction, etc.

Q. 23) Describe precision and recall.

Precision and recall are both measures that are used in the information retrieval domain to measure how well an information retrieval system reclaims the related data as requested by the user. Precision can be said to have a positive predictive value. It is the element of pertinent instances amongst the received instances.

On the other side, recall is the fraction of relevant instances that have been retrieved over the total number of relevant instances. The recall is also recognized as sensitive.

Q. 24) What do you understand by decision trees in machine learning?

Decision trees can be defined as supervised machine learning, where the data is continuously split according to a certain parameter. It builds classification or regression models similar to a tree structure, with datasets broken up into ever smaller subsets while developing the decision tree.

The tree can be distinguished by two objects, namely decision nodes and leaves. The leaves are the decision-or-node outcomes, and the decision-nodes are where the data is split. Decision trees can handle both categorical and numerical data.

Q. 25) What are the functions of supervised learning?

  1.             Classification
  2.             Speech Recognition
  3.             Regression
  4.             Predict Time Series
  5.             Annotate Strings

Q. 26) What are the functions of unsupervised learning?

  1.             Finding clusters of the data
  2.             Finding low-dimensional representations of the data
  3.             Finding interesting directions in data
  4.             Finding novel observations and database cleaning
  5.             Finding interesting coordinates and correlations

Q. 27) What do you understand by algorithm-independent machine learning?

Algorithm-independent machine learning can be demarcated as machine learning where mathematical fundamentals are self-governing of any specific classifier or learning algorithm.

Q. 28) Describe the classifier in machine learning.

A classifier is a case of a hypothesis or discrete-valued function that is used to assign class labels to particular data points. It is a scheme that contributes a course of separate or continuous feature values and outputs a single discrete value, the class. 

TOP 50 Machine Learning Interview Questions and Answers
TOP 50 Machine Learning Interview Questions and Answers

Q. 29) What do you mean by genetic programming?

Genetic programming (GP) is practically like transformative computing, a subset of AI. Genetic programming frameworks execute a calculation that utilizes irregular transformation, wellness capability, hybridity, and numerous ages of development to determine a client-characterized task. The genetic programming model depends on testing and picking the most ideal choice among a bunch of results. 

Q. 30) What is SVM in machine learning? Which are the classification methods that SVM can use?

SVM stands for Support Vector Machine. SVMs are supervised learning models with an associated learning algorithm that analyzes the data used for classification and regression analysis.

The classification methods that SVM can use are:

  •       Combining binary classifiers
  •       Modifying binary to incorporate multiclass learning

Q. 31) How will you enlighten a linked list and an array?

An array is a datatype that is widely implemented as a default type in almost all modern programming languages. It is used to store data of an analogous type.

But there are many use cases where we don’t know the quantity of data to be stored. For such cases, advanced data structures are required, and one such data structure is a linked list. 

Q. 32) What do you understand by the confusion matrix?

A confusion matrix is a table that is used to summarize the enactment of a classification algorithm. It is also recognized as the error matrix.

Q. 33) Explain true positive, true negative, false positive, and false negative in the confusion matrix with an example.

  •       True Positive

When a model properly envisages the positive class, it is said to be a true positive.

For example, the umpire provides a batsman NOT OUT when he is NOT OUT.

When a model properly envisages the negative class, it is said to be a true negative.

For example, the umpire provides a batsman OUT when he is OUT.

When a model wrongly predicts the positive class, it is said to be a false positive. It is also recognized as a ‘Type I’ error.

For example, the umpire gives a batsman NOT OUT when he is OUT.

When a model imperfectly predicts the negative class, it is said to be a false negative. It is also identified as a ‘Type II’ error.

For example, the umpire gives a batsman out when he is NOT OUT.

Q. 34) What, to you, is more important among model accuracy and model performance?

Model accuracy is a subset of model performance. The accuracy of the model is directly proportional to its performance. Thus, the better the performance of the model, the more accurate the predictions. 

Q. 35) What are bagging and boosting?

Bagging is a process in ensemble learning that is used to improve unstable estimation or classification schemes.

Boosting methods are used successively to decrease the bias of the combined model.

Q. 36) What are the similarities and differences between bagging and boosting in machine learning?

Similarities of Bagging and Boosting

  •       Both are ensemble methods to get N to learn from 1 learner.
  •       Both produce numerous training data sets with random sampling.
  •       Both produce the final result by captivating the average of N learners.
  •       Both decrease variance and deliver higher scalability.

Differences between Bagging and Boosting

  •       Although they are built independently, for bagging, boosting tries to add new models that perform well where previous              models fail.
  •       Only boosting controls the weight of the data to tip the scales in favor of the most stimulating cases.
  •       Only boosting tries to reduce bias. Instead, bagging may solve the problem of overfitting, while boosting can increase it.

Q. 37) What do you understand by cluster sampling?

Cluster sampling is the process of randomly selecting intact groups within a defined population that share similar characteristics. A cluster sample is a possibility where each sampling unit is a gathering or cluster of elements.

Q. 38) What do you know about Bayesian networks?

Bayesian networks, also referred to as ‘belief networks’ or ‘casual networks’, are used to signify the graphical model for probability association among a set of variables.

Q. 39) Which are the two components of the Bayesian logic program?

A Bayesian logic program contains two components:

It contains a set of Bayesian clauses that capture the qualitative structure of the domain.

It is used to encrypt quantitative data about the domain.

Q. 40) Describe dimension reduction in machine learning.

Dimension reduction is the process that is used to reduce the number of random variables under consideration.

Dimension reduction can be alienated into feature selection and extraction.

Q. 41) Why is an instance-based learning algorithm sometimes referred to as a lazy learning algorithm?

In machine learning, lazy learning can be labeled as a method where initiation and simplification processes are late until classification is executed. Because of this similar property, an instance-based learning algorithm is occasionally called a lazy learning algorithm.

Q. 42) What do you comprehend by the F1 score?

The F1 score signifies the measurement of a model’s performance. It is mentioned as a weighted average of the exactness and recall of a model. The results tending to 1 are considered the best, and those tending to 0 are the vilest.

Q. 43) How is a decision tree pruned?

Pruning is said to occur in decision trees when the branches that may contain weak predictive power are removed to reduce the complexity of the model and increase its predictive accuracy. Pruning can happen bottom-up and top-down, with approaches such as abridged error pruning and cost complexity pruning.

TOP 50 ML Interview Questions
TOP 50 ML Interview Questions

Q. 44) What are the recommended systems?

The Recommended System is a sub-directory of information filtering systems. It predicts the preferences or rankings offered by a user for a product. According to the preferences, it provides similar recommendations to the user. 

Q. 45) What do you understand by underfitting?

Underfitting is a problem when we have a low error in both the training set and the testing set. Few algorithms work well for interpretations but fail for better predictions. 

Q. 46) When does regularization become necessary in machine learning?

Regularization is necessary whenever the model begins to overfit or underfit. It is a cost term for transporting more features with the objective function. Hence, it tries to push the coefficients for many variables to zero and reduce the cost term. It helps to reduce model complexity so that the model can become better at predicting and generalizing.

Q. 47) What is regularization? What kind of problems does regularization solve?

A regularization is a form of regression that constrains, regularizes, or shrinks the coefficient estimates towards zero. In addition, it is disheartening to learn a more complex or flexible model to evade the danger of overfitting. It decreases the variance of the model, deprived of a substantial upsurge in its bias.

Regularization is used to discourse overfitting problems as it penalizes the loss function by adding a multiple of an L1 (LASSO) or an L2 (Ridge) norm of weights vector w.

Q. 48. Why do we need to convert categorical variables into factors? Which functions are used to carry out the conversion?

Most machine learning algorithms require numbers as input. That is why we change categorical values into factors to acquire numerical values. We also don’t have to contract with fake variables.

The functions factor () and factor () are used to convert variables into factors.

Q. 49) Do you think that considering a categorical variable as a continuous variable would result in a better predictive model?

For an improved predictive model, the categorical variable can be considered a continuous variable only when the variable is ordinal.

Q. 50) By what method is machine learning used in day-to-day life?

Most people are already using machine learning in their everyday lives. Assume that you are engaging with the internet and expressing your preferences, likes, and dislikes through your searches.

All these things are picked up by cookies coming to your computer; from this, the behavior of a user is evaluated. It helps to increase the progress of a user through the internet and provides similar suggestions.


Q: How can I stay informed about the modern trends in machine learning?

A: Stay active in online forums, read research papers, and participate in webinars and conferences. 

Q: What are some common mistakes to avoid during a machine learning interview?

A: Avoid memorizing answers; focus on understanding concepts. Also, be prepared to discuss your thought process.

Q: Is it necessary to have a deep understanding of mathematics for machine learning interviews?

A: While a strong mathematical foundation is beneficial, practical implementation and problem-solving skills are equally important.

Q: How can I showcase my practical experience in machine learning during an interview?

A: Highlight personal projects, open-source contributions, and any relevant work experience on your resume.

Q: Where can I find additional resources for machine learning interview preparation?

A: Online platforms like Coursera, Udemy, and Kaggle offer a wide range of courses, tutorials, and practice problems.

Get access all prompts: