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100+ Data Science Interview Questions and Answers {Interview Guide 2023}


Data science, the field of scientific methods, processes, and algorithms, is increasingly in-demand. The need and demand for skilled data scientists is expected to grow in the coming years. According to the US Bureau of Labor Statistics, employment of data scientists is projected to grow 11% from 2019 to 2029, faster than the average for all occupations.

While many people dream of working as a data scientist at leading digital companies. The competition and the need to upskill is also expanding. Cracking data science  interview questions is becoming more and more difficult. You need to have the required knowledge and expertise from fundamental to the advanced level in data analysis.  An effective way to begin your preparation for your journey as a data science professional is by enrolling in a Data Science Training Course for in-depth understanding or upskilling as per demand. Luckily, if you have secured yourself an interview appointment, this blog is for you.

Whether you're a seasoned data scientist or just starting out, we have prepared a list of data scientist interview questions and answers that will empower you with a solid foundation to build upon as you prepare for your interview. So let's get started – here are 100+ data science interview questions and answers to help you ace your next interview!

The Ultimate Guide of Data Science Interview Questions & Answers

Wondering how to prepare for data science interview? From technical questions about machine learning algorithms and data preprocessing to questions about your problem-solving and communication skills based on a comprehensive data science career path, we've got you covered.

1) What is Data Science?

Ans:-  Data science implies a field that uses scientific methods, processes, algorithms, and systems to extract knowledge and insights from structured and unstructured data. It involves using a combination of statistical analysis, machine learning techniques, and domain expertise to uncover patterns, trends, and relationships in data, and to generate predictions or decisions based on that data.

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2) What is the difference between Data Analytics, Big Data, and Data Science?

Ans:-  Here is how you can explain Big Data, Data Analytics and Data science to state the differences accordingly- 

  1. Big Data: Big Data is a field that deals with huge data volumes in structured and semi structured form and requires just basic knowledge of statistics and mathematics.
  2. Data Analytics: Data Analytics is a field that provides the operational insights of various complex scenarios of a business. 
  3. Data Science: Data Science is a field that deals with slicing and dicing of data. Data scientists are required to have deep knowledge of statistics and mathematics. 

3) Which language R or Python is most suitable for text analytics?

Ans:-  When one compares R or Python, as Python consists of a rich library of Pandas, the analysts can use high-level data analysis tools and data structures, this feature is absent in R, so Python is more suitable for text analytics.

4) Explain Recommender System.

Ans:-  This question is among the most commonly asked interview questions for data scientists.

The recommended system works based on the past behavior of the person. It uses the discrete characteristics of the items to recommend any additional item. It is widely deployed in several fields like music preferences, movie recommendations, research articles, social tags, and search queries. With this system, the future model can also be prepared, which can predict the person’s future behavior and can be used to know the product the person would prefer to buy, which movie he will view, or which book he will read.

5) What are the benefits of the R language?

Ans:-  R programming uses several software suites for statistical computing, graphical representation, data calculation, and manipulation. Following are a few characteristics of R programming:

  • It has an extensive tool collection
  • Tools have the operators to perform Matrix operations and calculations using arrays
  • Analyzing techniques using a graphical representation
  • It is a language with many effective features but is simple as well 
  • It supports machine-learning applications
  • It acts as a connecting link between several data sets, tools, and software
  • It can be used to solve data-oriented problem

6) How do Data Scientists use statistics?

Ans:-  With the help of statistics, Data Scientists can convert a huge amount of data to provide insights. The data insights can provide a better idea of what the customers are expecting. With the help of statistics, Data scientists can know the customer’s behavior, engagements, interests, and final conversion. They can make powerful predictions and certain inferences. It can also be converted into powerful propositions of business, and the customers can also be offered suitable deals. It is among the popular statistics interview questions for the data scientist.

7) What is the importance of data cleansing in data analysis?

Ans:-  As the data come from various multiple sources, it becomes important to extract useful and relevant data, and therefore data cleansing becomes very important. Data cleansing is basically the process of correcting and detecting accurate and relevant data components and the deletion of irrelevant ones. For data cleansing, the data is processed concurrently or in batches.

Data cleansing is one of the essential steps for data science, as the data can be prone to errors for several reasons, including human negligence. It can also take a lot of time and effort to cleanse the data, as it comes from various sources. This is why data cleansing-related questions are added to this data science question list and often taught in data scientist certification online courses.

8) In a real-world scenario, how will machine learning be deployed?

Ans:-  This is among the most commonly asked data science interview questions.

The real-world applications of machine learning include:

  • Finance: To evaluate risks, investment opportunities and in the detection of fraud
  • Robotics: To handle the non-ordinary situations
  • Search Engine: To rank the pages as per the user’s personal preferences
  • Information Extraction: To frame the possible questions to extract the answers from the database
  • E-commerce: To deploy targeted advertising, re-marketing, and customer churn.

9) What is Linear Regression?

Ans:-  It is among the best data scientist interview questions for freshers. 

Linear regression is used for predictive analysis. This method describes the relationship between dependent and independent variables. In linear regression, a single line is fitted within a scatter plot. It consists of the following three methods:

  • Analyzing and determining the direction and correlation of the data
  • Deployment of the estimation model
  • To ensure the validity and usefulness of the model. It also helps to determine the outcomes of various events.

10) Explain the K-means algorithm.

Ans:-  This is one of the most discussed data science interview questions and answers.

K-Means is a basic and unsupervised learning algorithm that uses data clusters, known as K-clusters, to classify the data. The data similarity is identified by grouping the data. The K centers are defined in each K cluster. The K groups are formed using K clusters, and K is performed. The objects are assigned to their nearest cluster center. All objects of the same cluster are related and different from the objects of other clusters. This algorithm is the best for large sets of data.

11) What is a Confusion Matrix?

Ans:-  Another data science question you should know to answer. The Confusion Matrix, an n×n matrix, assesses how well the categorization model performs. The confusion matrix summarizes the results of a certain problem's predictions. It is a table that is used to summarize the model's performance.

12) How well-versed are you in true-positive and false-positive rates?

Ans:-  Positive rate: The proportion of accurate predictions made for the positive class is indicated by the true-positive rate. The accurate percentage of actual positives that are verified is also calculated using this metric.

False-positive rate: The false-positive rate shows the percentage of inaccurate predictions made for the positive class. When something is erroneous, a false positive determines it is true.

If you want to succeed in your interviews, it is important to be aware of all the important concepts of data science. You should be aware about your duties and what exactly does a data scientist do? 

13) Mention a few sample strategies. What is sampling's main benefit?

Ans:-  It is among the best data scientist interview questions for freshers. 

Sampling is the process of choosing specific individuals or a small portion of the population to gauge the characteristics of the entire population. Probability and Non-Probability Sampling are the two types of sampling. It is among the popular interview questions for the data scientist.

14) Why does Data Cleaning in DS employ Python?

Ans:-  It is another important data science question to ask. Technical analysts and data scientists must transform vast data into useful ones. Malicious entries, outliners, incorrect values, and unnecessary formatting are removed during data cleaning. The two most popular Python data cleaners are Matplotlib and Pandas. 

15) Talk about Artificial Neural Networks

Ans:-  This is one of the most discussed data science interview questions and answers.

Machine learning has been transformed by a unique group of algorithms called artificial neural networks (ANN). It aids in your ability to adjust to shifting input. As a result, the network produces the best outcome without changing the output criteria.

16) What is Back Propagation, exactly?

Ans:-  The foundation of neural net training is back-propagation. The process of fine-tuning a neural network's weights is based on the error rate recorded in the previous epoch. Proper tuning can help you lower error rates and increase model reliability by boosting the model's generalization.

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17) What is a Random Forest?

Ans:-  This is one of the important data scientist interview questions for experienced.

 A random forest machine learning technique enables you to complete all kinds of regression and classification tasks. It is also employed to treat missing values and outlier values. It is one of the most frequently asked interview questions in data science.

18) What significance does a selection bias have? 

Ans:-  When picking people, groups, or data to be evaluated, no precise randomization is implemented, which results in selection bias. It implies that the population intended for analysis is not accurately represented by the sample used. It is among the popular interview questions for the data scientist. 

19) Describe the K-means clustering technique.

Ans:-  It is among the best data scientist interview questions for freshers. 

An important unsupervised learning technique is K-means clustering. It is a method for categorizing data using a specific set of clusters known as K clusters. It is utilized for grouping to determine data similarity.

20) Describe the differences between data analytics and data science.

Ans:-  The primary distinction between the two is that data scientists possess higher technical expertise than business analysts. Additionally, they don't require the business knowledge necessary for data visualization. For a data analyst to apply these useful insights to business scenarios, data scientists must slice the data.

21) What is a p-value?

Ans:-  This is among the most commonly asked interview questions for data scientists.

A p-value allows you to assess the significance of your findings while performing a hypothesis test in statistics. It is an integer in the range of 0 and 1. You can determine the exact result's strength based on the value.

22) What is deep learning?

Ans:-  A subcategory of machine learning is deep learning. It focuses on algorithms influenced by artificial neural network construction (ANN).

23) Describe the procedure for gathering and analyzing data to use social media to forecast weather conditions.

Ans:-  The Facebook, Twitter, and Instagram APIs can gather social media data. For the tweeter, for instance, we can create a feature from each tweet, such as the date it was posted, the number of retweets, a list of followers, etc. The weather can then be forecast using a multivariate time series model. It is one of the other important data science questions to ask. 

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24) When should data science algorithms be updated?

Ans:-  This is one of the most discussed data science interview questions and answers.

  • You want your data model to develop using infrastructure as data streams do.
  • The source of the underlying data is evolving.
  • If non-stationarity is present. 

25) The law of huge numbers is what?

Ans:-  This is one of the important data scientist interview questions for experienced.

The idea of frequency-style thinking is based on this theory. It is a theorem explaining what happens when you repeat an experiment. The sample means, sample variance, and sample standard deviation are said to converge to the estimate. It is among the popular interview questions for the data scientist. It is among the most frequently asked interview questions in data science.

26) What factors are confusing?

Ans:-  These are extra variables in a statistical model that correlate with the dependent and independent variables, either directly or inversely. The confounding factor is not taken into account in the estimate.

27) What is a star schema?

Ans:-  It has a central table and follows a conventional database schema. Satellite tables, also known as lookup tables, are most helpful in real-time applications because they save a significant amount of memory. They link IDs to physical names or descriptions and can be connected to the central fact table via the ID fields. To recover information more quickly, star schemas occasionally use multiple summarization levels.

28) What are exploding gradients?

Ans:-  This is among the most commonly asked interview questions for data scientists.

Ans. The scenario known as "exploding gradients" is troublesome because it causes unusually significant modifications to the weights of neural network models during training. In a worst-case scenario, the weight value could overflow and produce NaN values. As a result, the model loses stability and cannot gain knowledge from the training set.

29) What is the Law of Large? 

Ans:-  According to the "Law of Significant Numbers," if an experiment is independently conducted a large number of times, the average of the individual results will be quite near to the value predicted. Additionally, it says that the sample variance and standard deviation are heading toward the predicted value.

30) What role does A/B testing play?

Ans:- The objective of A/B testing is to select the superior of two hypotheses. Examples of this type of testing applications include:

  • Testing the responsiveness of web pages or applications.
  • Redesigning landing pages.
  • Testing banners.
  • Measuring the effectiveness of marketing campaigns.

Confirming a conversion target comes first, then statistical analysis is utilized to determine which alternative works best for the specified conversion objective.

31) What is a computational graph?

Ans:-  This question is one of the most frequently asked interview questions in data science. 

A "Dataflow Graph" is another name for a computation graph. TensorFlow is a well-known deep learning framework built entirely on the computational graph. Tensorflow's computational graph consists of a network of nodes, each of which has an associated function. In this network, the nodes stand in for operations and the edges for tensors.

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32) What are auto-encoders?

Ans:-  This is one of the most discussed data science interview questions and answers.

Learning networks are auto-encoders. They convert inputs into outputs with the fewest faults feasible. This means that the output we seek should be almost identical to or as near the input as possible.

Further layers are added between the input layer and the output layer, and these additional levels are smaller than the input layer.

33) Explain how a box plot and a histogram differ.

Ans:-  This is among the most commonly asked data science interview questions. Histograms and box plots are examples of visualizations that depict data distributions for effective information sharing.

Histograms are bar chart depictions of data that shows the frequency of numerical variable values and can be used to estimate outliers, variations, and probability distributions.

Boxplots are used to communicate various features of data distribution where the distribution's form cannot be observed but still allows for gathering insights. This helps compare several charts simultaneously because they take up less space than histograms.

34) What is a computational graph?

Ans:-  A "Data flow Graph" is another name for a computation graph. TensorFlow is a well-known deep learning framework built entirely on the computational graph. Tensorflow's computational graph consists of a network of nodes, each of which has an associated function. This graph's edges correspond to tensors, while its nodes correspond to operations. It is among the popular interview questions for data scientists. 

35) What is dimension reduction? Why is it advantageous?

Ans:-  Dimensionality reduction transforms a large data collection into smaller data sets to communicate similar information more succinctly.

The main advantages of this technique are data compression and storage space reduction. Due to the smaller number of dimensions, it is also helpful in speeding up computations. Finally, it facilitates the removal of extra features; for example, it prevents the storage of a value in two separate units (inches and meters).

36)How should a deployed model be maintained?

Ans:-  A deployed model must be retrained after a while to increase model performance. Since deployment, a record of the model's predictions and the actual values should be kept. This can then be utilized to retrain the model using fresh data. The underlying causes of inaccurate predictions should also be investigated.

37) Explain Eigenvalue and Eigenvector.

Ans:-  This is among the most commonly asked interview questions on data science.

For understanding linear transformations, use eigenvectors. Data scientists must compute a covariance matrix or correlation's eigenvectors. The directions that a particular linear transformation acts by compressing, flinging, or stretching are known as eigenvalues.

38) Describe the cross-validation.

Ans:-  It is among the best data scientist interview questions for freshers. 

An evaluation method for gauging the generalizability of statistical analysis results for an independent dataset is cross-validation. This approach is utilized when a model's accuracy needs to be estimated, and the goal is to forecast a future state.

39) What is Collaborative filtering?

Ans:-  With the help of collaborative filtering technology, users can exclude items based on the opinions of other users who share their interests. It operates by looking through a big group of people and identifying a smaller group of users with tastes comparable to a certain user.

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40) What is Star Schema?

Ans:-  A data warehousing concept known as "star schema" connects all schemas to a single central schema. This is one of the important data scientist interview questions for experienced.

41) What is RMSE?

Ans:- This is one of the most discussed data science interview questions and answers.

The root means the square error is referred to as RMSE. It is a metric for regression accuracy. We can determine the severity of an error caused by a regression model using the RMSE.

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42) What does an SVM kernel function do?

Ans:- A kernel function in the SVM method is a unique mathematical operation. Simply put, a kernel function transforms data into the necessary form after receiving it as input. The kernel function gets its name because its data transformation is based on a kernel trick.

43) How do we handle outliers?

Ans:-  There are numerous techniques to handle outliers. Dropping them is one option. Only if the outliers have extreme or inaccurate values may we discard them. For instance, it would be inaccurate if a dataset of baby weights contained a figure of 98.6 degrees Fahrenheit. However, if the value is 187 kg, that is an extreme amount and not one that our model can employ.

44) Describe how recommender systems use content-based filtering.

Ans:-  One method used to create recommender systems is content-based filtering. This method uses the characteristics of the content that a user is interested in to generate suggestions.

45) Explain bagging in Data Science.

Ans:-  This is among the most commonly asked data science interview questions.

An approach to group learning is bagging. Bootstrap aggregating is an acronym. Using an existing dataset and many samples of the N size, we produce some data using the bootstrap method in this methodology. Using this bootstrapped data to train several models concurrently, the bagging model is strengthened over a simple model.

46) Explain boosting in Data Science.

Ans:-  One of the ensemble learning strategies is boosting. In boosting, we build many models and train them sequentially by iteratively combining weak models so that teaching a new model depends on training models taught earlier. It is not a method used to train our models in parallel, in contrast to bagging.

47) What is reinforcement learning?

Ans:-  A subset of machine learning called reinforcement learning focuses on creating software agents that take behaviors to earn the highest cumulative rewards.

Here, a reward is utilized to inform the model (during training) if a specific activity results in the accomplishment of or moves it closer to the objective.

48) Explain TF/IDF vectorization

Ans:-  This is among the most commonly asked data science interview questions.

Term Frequency-Inverse Document Frequency is the meaning of the abbreviation "TF/IDF." In text mining and information retrieval, TF/IDF is frequently employed. A quantitative measurement enables us to ascertain a word's significance to a document inside a corpus, a collection of documents.

49) What does the P-value mean in terms of statistics?

Ans:-  In statistics, the p-value is used to determine if a null hypothesis is significant. If the p-value is less than 0.05, the null hypothesis must be rejected because there is only a 5% probability that an experiment's results are random. On the other hand, a larger p-value, say 0.8, indicates that the null hypothesis cannot be ruled out because random outcomes occur in 80% of the sample. 

50) Why do we employ A/B Testing? 

Ans:-  Determine which product version is most likely to function better than the other. The technique of A/B Testing is used to analyze user experience. It requires providing the user with two different product versions. Additionally, user preferences are understood through Testing.

51) What is the normal distribution's standardized form?

Ans:-  A unique type of normal distribution with a mean of 0 and a standard deviation of 1 is known as the standard normal distribution or z-distribution. By transforming the values of any normal distribution into z scores, it is possible to standardize it. Z scores provide the number of standard deviations from each value's mean.

52) What does the term "hypothesis" in the context of machine learning mean to you?

Ans:-  A hypothesis in machine learning is a mathematical function that an algorithm uses to depict the association between the target variable and features.

53) What distinguishes AUC from ROC?

Ans:-  Precision is measured against recall using the AUC curve. Precision is equal to (TP)/(TP + FP) and (TP)/(TP + FN). In contrast, ROC assesses and graphs the ratio of true positives to false positives.

54) Define a confusion matrix. 

Ans:-  This is among the most commonly asked data science interview questions.
A table that describes how a supervised learning algorithm is performed is known as a confusion matrix. It gives an overview of the outcomes of a classification problem prediction. You can identify the types of errors made by the predictor and the errors themselves with the confusion matrix.

55) Describe the Normal Distribution.

Ans:-  A probability distribution known as a "normal distribution" has symmetrical values on either side of the data's mean. The implication is that values closer to the mean are more frequent than values furthest from it. It is among the best data scientist interview questions for freshers. 

56) Explain Deep Learning. 

Ans:-  Artificial neural networks and deep learning are a subclass of machine learning focusing on supervised, unsupervised, and semi-supervised learning.
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57) RNN (Recurrent Neural Network): What Is It?

Ans:-  An artificial neural network, a recurrent neural network, bases the connections between its nodes on a time series. The only type of neural network with internal memory is an RNN, frequently employed in speech recognition applications.

58) Explain the ROC Curve.

Ans:-  ROC curves are graphs that show a classification model's performance at various thresholds for classification. The True Positive Rate (TPR) and False Positive Rate (FPR) are plotted on the graph's y and x axes, respectively. You can learn more about ROC curves and many more essential data science concepts through online data science tutorials and training courses. Taking a course before applying for a new position always helps you upskill as per recent demands and be ready for all possible interview questions that come your way..  

59). What Qualifies Time-Series Data as Stationery?

Ans:-  This is among the most commonly asked data science interview questions. When data from a time series is deemed stationary, there has been no change in the data throughout time. This could result from the data's lack of seasonal or time-based tendencies.

60) What Purpose Does the Summary Function Serve?

Ans:-  The output of several model-fitting functions is summarized via summary functions. For instance, the summary() function in R can be used to quickly compile a summary of your dataset and the output of a machine learning method.

61) Tell us about ensemble learning.

Ans:-  A machine learning technique known as ensemble learning employs many models to boost a data analysis model's ability to predict the future.

62). Why Do You Use the Term "Bagging"?

Ans:-  An ensemble learning method called bagging is used to lessen the variance in a noisy dataset.

63) Explanation about data science boosting

Ans:-  This is among the most commonly asked data science interview questions. A weak learning model can be strengthened using the ensemble learning technique known as boosting.

64) Describe Naive Bayes.

Ans:-  The Naive Bayes classification algorithm assumes that each feature is independent. That same assumption, frequently unfounded given data from the real world, is why it is referred to as naive. It does, however, frequently perform successfully in resolving various issues.

65) What makes recall and precision different from one another?

Ans:-  The proportion of events labeled as true is known as recall. Precision, however, measures the weighting of genuinely true instances. Precision is a genuine value that shows factual information, whereas recall is an estimate.

66) What does Python's pickle module do?

Ans:-  This is among the most commonly asked data science interview questions. Python's pickle package is used to serialize and deserialize objects. It turns a character stream from an object structure. We employ Pickle to store this object on the drive.

67) How would you define data integrity?

Ans:-  Data correctness and consistency can both be defined in terms of data integrity. Throughout its whole existence, its integrity must be guaranteed.

68) How would you approach a gradient explosion problem?

Ans:-  One can carefully build the network of a model and prevent bursting gradients by sticking to a limited learning rate, scaled target variables, and a standard loss function. Using gradient scaling or clipping to modify the error before it is transmitted across the network is another method for dealing with ballooning gradients. This modification of the mistake enables weight rescaling.

69) What are exploding gradients?

Ans:-  Exploding gradients occur when significant error gradients build up and cause massive modifications to the weights of neural network models during training. 

70) What exactly do you mean by clustering?

Ans:-  This is among the most commonly asked data science interview questions. By grouping the data points into several groups, clustering can be used to determine which groups' data points are most similar to one another. These collections are referred to as clusters, and as a result, similarities within clusters are greater than those between clusters.

71) What does "data warehouse" mean?

Ans:-  The data warehouse is a system for reporting and analyzing data gathered from various operational systems and sources. Data warehouses have a crucial function in Business Intelligence.

72) Which is superior, good models or good data?

Ans:- Positively, good data is more crucial than good models. The quality of the data is what aids in the creation of an effective model. If the model is fed better-quality data, its accuracy will rise. Data preparation is crucial before training the model because of this.

73)What are recommender systems?

Ans:-  A type of information filtering system called a recommender system predicts how users will rank or score specific things (movies, music, merchandise, etc.). The preferences and interests of the user are taken into account as recommender systems filter huge amounts of data depending on the information provided by the user and other variables.

74) How much data is required to produce a reliable result?

Ans:-  This is among the most commonly asked data science interview questions. All businesses are unique and are evaluated in various ways. There will, therefore, never be enough information and no correct response. The quantity of information needed relies on the techniques you employ to have a great possibility of generating important results.

75) What distinguishes "anticipated value" from "average value"?

Ans:-  There are no differences between the two in terms of functioning. They are utilized in many contexts, though. The average value reflects the population sample, whereas an expected value typically reflects random variables.

76) Explain the differences between single-, bi-, and multivariate analyses.

Ans:-  The simplest type of statistical analysis, known as a univariate analysis, only considers one variable.

Two variables are investigated in a bivariate analysis, and many variables are examined in a multivariate analysis.

77) How does association analysis work? How does it function?

Ans:-  Association analysis is the process of identifying connections between data. It is employed to comprehend the relationships between the data elements.

78) Root Cause Analysis: What is it?

Ans:-  Root Cause is referred to as a process's core failure. Root Cause Analysis is a methodical strategy that has been developed to investigate such problems (RCA). With this approach, a problem or mishap is addressed, and the "root cause" is discovered.

79) What distinguishes a Validation Set from a Test Set?

Ans:-  Overfitting is reduced by using the validation set. This aids in determining whether there has been an accuracy improvement over the training data set and is used in parameter selection. A trained machine learning model is tested and evaluated using a test set.

80) The Confusion Matrix: What Is It?

Ans:-  This is among the most commonly asked data science interview questions.

The confusion matrix is a highly helpful tool for evaluating the quality of a machine learning-based classification model. It can be used to assess the effectiveness of a classification model and is also referred to as an error matrix. The count numbers are used to summarize the number of accurate and inaccurate predictions for each class.

81)Describe the Root Cause Analysis.

Ans:-  Root cause analysis (RCA) is the process of locating the underlying causes of issues in order to determine the most effective solutions. The RCA makes the assumption that systematically preventing and resolving fundamental problems is considerably more beneficial than simply treating symptoms as they arise and putting out fires.

82) What is correlation analysis?

Ans:-  The statistical method of correlation analysis is used to assess how closely two quantitative variables are related. It is made up of autocorrelation coefficients that have been evaluated and computed to form various geographical relationships. Data based on distance are correlated using it.

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83) What exactly is a hypothesis test?

Ans:-  This is among the most commonly asked data science interview questions.

The analysis of various elements that can have an impact on the result of the experiment is a crucial part of any testing procedure in machine learning or data science.

84) What distinguishes supervised from unsupervised machine learning in particular?

Ans:-  Unsupervised learning does not necessitate explicitly labeling data, whereas supervised learning uses training sets of labeled data for a variety of tasks, including data classification.

85) Describe KNN.

Ans:-  K-Nearest Neighbor, sometimes known as KNN, is a straightforward machine learning algorithm built on the Supervised Learning approach. The new case is positioned closest to the available categories based on the assumption that the new case's data and existing instances are similar.

86) What do you mean when you refer to long and wide data formats?

Ans:-  There is a column in broad data format for each variable in the dataset. The dataset, on the other hand, has a column for each of the different variable types and a column for the values of those variable types in a long format.

87) How do you interpret the extrapolation and interpolation of the provided data?

Ans:-  When one interpolates data, they are estimating the values of a variable from the dataset that lie between two known values. On the other hand, projecting the data entails estimating values outside a variable's range.

88) Does gradient descent always lead to the same result?

Ans:-  This is among the most commonly asked data science interview questions.

Because they sometimes converge to a local minimum or a local optima point, gradient descent algorithms do not always converge to the same place. It heavily depends on the data being used and the learning parameter's initial settings.

89) What is the curse of dimensionality?

Ans:-  High-dimensional data refers to data that has a large number of features. The dimension of data is the number of features or attributes in the data. The problems arising while working with high-dimensional data are referred to as the curse of dimensionality. It basically means that error increases as the number of features increases in data. Theoretically, more information can be stored in high-dimensional data, but practically, it does not help as it can have higher noise and redundancy. It is hard to design algorithms for high-dimensional data. Also, the running time increases exponentially with the dimension of data.

90) What is the use of the R-squared value?

Ans:-  The r-squared value compares the variation of a fitted curve to a set of data points with the variation of those points with the line that passes through the average value. It can be understood with the help of the formula. 

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91) Describe the central limit theorem.

Ans:-  This is among the most commonly asked data science interview questions.

The central limit theorem states that regardless of the distribution each sample follows, if a large number of samples of a population are taken, the distribution spread of their mean values will follow a normal distribution curve.

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92) How does the central limit theorem apply to a group of social science freshmen with little background in statistics?

Ans:-  The central limit theorem's most significant repercussion demonstrates how frequently nature follows the normal distribution curve. Experts in various disciplines, including statistics, physics, mathematics, computer sciences, etc., can assume that the data they are examining follows the well-known bell curve.

93) What is Dropout?

Ans:-  In data science, "dropout" refers to randomly removing visible and hidden network units. Removing up to 20% of the nodes can avoid overfitting the data and create the space needed for the network's iterative convergence process.

94) What is an epoch?

Ans:-  In data science, an epoch is a single iteration through the whole dataset. Everything that is used with the learning model is included.

95) What Exactly Is a Batch?

Ans:-  A batch is a collection of the data set's broken-down collections that aid in transferring data into the system. It is used when the developer can't feed the complete dataset at once into the neural network.

96) What is an iteration, exactly?

Ans:-  A classification of the data into various groups used during an epoch is called an iteration.

97) What is batch normalization?

Ans:-  This is among the most commonly asked data science interview questions.

What is batch normalization? To accomplish this, normalize the inputs in each layer such that the mean output activation stays at 0 and the standard deviation is set to 1.

98) How is backpropagation implemented? 

Ans:-  A multilayer neural network training algorithm is known as backpropagation. By using the backpropagation technique, the error is propagated from one end of the network to all its weights. This makes it possible to compute the gradient quickly.

99) How well-versed are you in autoencoders?

Ans:-  Simple learning networks called autoencoders to convert inputs into outputs as accurately as feasible. This indicates that the output's results are close to the inputs.

100) Describe GAN.

Ans:- This is among the most commonly asked data science interview questions.

To recognize and distinguish genuine from fraudulent inputs, the Generative Adversarial Network takes inputs from the noise vector and forwards them to the Generator and Discriminator.

101) Describe tensors.

Ans:- Tensors are mathematical constructs that describe the collection of higher dimensions of data inputs sent to the neural network in the form of letters, numbers, and ranks.


Data science interviews can be intimidating due to the wide range of topics that may be covered. However, by reviewing and practicing common data science interview questions and answers, you can increase your confidence and improve your chances of getting shortlisted. It is important to be familiar with the basics of programming, statistics, machine learning, and data visualization, as well as to have a strong understanding of the business problem you are trying to solve. Additionally, it can be helpful to have experience working with real-world data and a portfolio of projects to showcase your skills. 

I hope this set of Data Science Interview Questions and Answers will help you in preparing for your interviews. By preparing in advance or taking a data science training course you can learn or sharpen your skills to successfully navigate a data science interview and take the next step in your career. JanBask Training has a specially curated Data Science Training that helps you gain the required expertise and makes you job-ready. Do you have any questions for us? Please let us know in the comments section, and we will get back to you soon. All the best! 


    Janbask Training

    A dynamic, highly professional, and a global online training course provider committed to propelling the next generation of technology learners with a whole new way of training experience.

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