The field of data science is rich with terminology that can be overwhelming for newcomers. Whether you’re a budding data scientist or a seasoned professional, learning data science glossary is important for data science interviews.
As the field of data science is becoming competitive everyday, learning the key terminologies is essential. This knowledge will help you become job ready. Further, it will also boost your confidence and enable you to be efficient and perform better at the job.
In this article, we have prepared a data science glossary that covers key terms from A to Z and provides a comprehensive reference for the most important concepts in data science. You can use this glossary for your data science interview preparations.
Also read: Data Engineer Interview Process
Data Science Glossary from A-Z
If you’re preparing for data science interview questions, then you must be well-versed in the data science glossary.
Here’s a detailed data science glossary that covers all the key terms alphabetically:
A
Algorithm
It is a list of rules to follow to solve a certain problem or complete various tasks. In data science, algorithms are used for things like analysis, prediction, and building models.
Artificial Intelligence (AI)
Simulating human intelligence processes by machines.
Anomaly Detection
Anomaly detection is the ability to discover unusual patterns that do not align with expected behavior. It is used as complementary data for fraud detection, network security, and predictive maintenance.
Accuracy
It is a measure of how often a model correctly predicts or classifies outcomes. It is the ratio of the number of correct predictions to the total number of predictions made, expressed as a percentage.
B
Big Data
Big data is a term in use for a long time to define data that are so large, complex, and beyond our abilities of updates. The features of big data are the 3 V’s: volume, velocity, and variety.
Bias
Bias is the systematic error that occurs in data or models used by a data scientist and propagates into incorrect conclusions. Bias arises when data are collected improperly, the sample is not truly representative, or this influence was introduced to algorithm writing.
Business Intelligence (BI)
All the strategies and technologies business analysts should use in enterprise BI. Business intelligence tools help in data-driven decision-making as they provide historical, current, and predictive views of business operations.
C
Classification
The process of categorizing data into predefined classes or labels is called classification, and it is a supervised learning technique. Compared to a decision tree, linear regression, and support vector machines are popular choices for classification.
Clustering
Clustering is an unsupervised learning method where similar features are grouped. Common clustering algorithms are K-means, hierarchical clustering, and DBSCAN.
Cross-Validation
Cross-validation is a technique to assess the performance of your machine learning model, based on how well it does in making predictions. This consists of dividing the data many times into training and testing sets to test if our model generalizes well on new data points.
Also read: Data Scientist Salary in the United States
D
Data Cleaning
Data cleaning (or data pre-processing) includes removing inaccuracies, inconsistencies, and other errors from the data. This is an important step to ensure quality and reliability of data that will be used in analysis.
Data Mining
Data mining is the practice of finding patterns and anomalies in large datasets. It leverages methods of statistics for data science, machine learning, and database systems to uncover actionable knowledge.
Deep Learning
Deep learning is a type of machine learning that employs neural networks with many layers (deep neural networks) to model complex patterns in data. Therefore, the model can be well-suited to image and speech recognition.
Data Modeling
Data modeling involves creating a visual representation of a complex system’s data, showing how different data elements relate to each other.
Data Visualization
Data visualization is the graphical representation of information and data using visual elements like charts, graphs, and maps.
E
Ensemble Learning
Ensemble learning is the method of combining multiple machine learning models to improve overall performance and accuracy. Ensemble methods include techniques like bagging, boosting, and stacking.
ETL (Extract, Transform, Load)
The ETL process extracts data from disparate source systems, transforms the data into a format that fits your target system, and finally loads it into some type of focused repository.
Exploratory Data Analysis (EDA)
Exploratory data analysis is an approach to analyzing datasets to summarize their main characteristics, often using visual methods. This is useful to understand the data distribution, analysis patterns, and detect anomalies.
F
False Negative
A test result that incorrectly comes out negative, indicating the absence of a condition when this is not true.
False Positive
Incorrectly predicting a positive outcome (which is negative in reality) by the model.
Forecasting
Forecasting requires predicting future values based on past data. It is common in business planning, financial analysis, and supply chain management.
Feature Engineering
Feature engineering is the process of using domain knowledge to extract features from raw data that make machine learning algorithms work more effectively.
G
Gradient Descent
Gradient descent is a first-order iterative optimization algorithm for finding the minimum of functions. Most commonly, it tries to minimize some loss function in machine learning models. The model parameters are updated iteratively to obtain the optimal solution.
Graph Analytics
Graph analytics is the analysis of data that are graph-based, identifying the relationships, patterns, and properties. It contributes to social network analysis, recommendation systems, and fraud detection.
Grid Search
Grid search is a hyperparameter tuning method to find the optimal parameters for an estimator. It loops over every single combination of parameters you gave it a range to check out and will help tune your model process by exhaustively searching through the grid.
Also read: Data Science Vs Software Engineer
H
Hyperparameter
Hyperparameters are parameters established before the learning process and dictate much of the behavior of the algorithm used in machine learning. This includes hyperparameters like the learning rate, number of trees in a random forest, and regularization parameters.
Hypothesis Testing
Hypothesis testing is a statistical method used in inferential statistics for data science to conclude if there is enough evidence to reject a null hypothesis. It is commonly used in scientific research and A/B testing.
Hadoop
Hadoop is a distributed computing environment. It is described as an open-source software framework that enables the storage and processing of big data in a distributed computed environment. It scales from a single server to thousands of machines.
I
Imbalanced Data
When the classes in a classification problem are not equally represented, this results in imbalanced data. Imbalanced data sets lead to biased models and remedies like resampling (including SMOTE) and adjusting class weights are needed.
Inferential Statistics for Data Science
Inferential statistics for data science involves making inferences about a population based on data sampled from it. This includes techniques like:
- Confidence intervals
- Hypothesis testing
- Regression analysis
Internet of Things (IoT)
The IoT (Internet of Things) is the network of physical objects connected to sensors, software, and various other technologies for connecting and exchanging data. IoT produces a lot of data that can be examined and used for reasoning.
J
JavaScript Object Notation (JSON)
JSON is a lightweight data exchange format that helps to transmit the data between a server and web application. It is human-readable and writable, so it is used wherever data has to be transmitted between distantly located services in APIs and URL parameters.
K
K-Means
A K-means clustering algorithm in which data points are grouped into K clusters, each with its cluster mean.
Keras
A high-level neural networks API, written in Python and capable of running on top of TensorFlow, or other popular deep learning libraries.
Also read: Data Analyst vs. Data Scientist: Main Difference
L
Linear Regression
Linear regression is widely used in practical applications, including fields such as data mining, machine learning and statistics for data science are only few examples among others where linear regression is applied. It allows predictive analytics and assumes that all variables have a linear relationship.
Logistic Regression
Logistic regression is a type of classification that fits the log-odds probability. It is the function of a feature and target variable probability plot based on a logistic function which we already know.
Long Short-Term Memory (LSTM)
LSTM is a type of recurrent neural network (RNN) designed to model sequential data and capture long-term dependencies. It is widely used in natural language processing and time series forecasting.
M
Machine Learning
Machine learning is a subset of AI that involves training algorithms to learn patterns from data and make predictions or decisions. It includes supervised, unsupervised, and reinforcement learning.
Model Evaluation
Model evaluation involves assessing the performance of a machine learning model using metrics such as accuracy, precision, recall, F1 score, and ROC-AUC. It helps determine how well the model generalizes to new data.
Monte Carlo Simulation
Monte carlo simulation is a computational technique used to model the probability of different outcomes in complex systems. It uses random sampling to estimate statistical properties and predict future events.
N
Natural Language Processing (NLP)
Natural language processing (NLP) is an area of AI focused on the interaction between computers and human language. It involves processing and analyzing text data to enable tasks such as sentiment analysis, machine translation, and chatbot development.
Neural Network
A neural network is a computational model inspired by the structure and function of the human brain. It consists of interconnected nodes (neurons) that process and transmit information, enabling tasks such as image recognition and natural language understanding.
Normalization
Normalization is a data preprocessing technique used to scale numerical features to a common range. It helps improve the performance and stability of machine learning algorithms.
O
Overfitting
Overfitting occurs when a machine learning model learns the noise and details of the training data too well, resulting in poor generalization to new data. Techniques like cross-validation, regularization, and pruning can help prevent overfitting.
Outliers
Outliers are data points that deviate significantly from the majority of the data. They can indicate errors, variability, or novel insights and need to be carefully handled in data analysis.
Optimization
Optimization involves finding the best solution to a problem by maximizing or minimizing an objective function. In machine learning, optimization techniques are used to train models by adjusting parameters to minimize loss.
Also read: Essential Skills Every Data Analyst Must Master in 2024
P
Principal Component Analysis (PCA)
PCA is a dimensionality reduction technique used to transform high-dimensional data into a lower-dimensional space. It identifies the principal components that capture the most variance in the data.
Precision
Precision is a metric used to evaluate the accuracy of a classification model. It measures the proportion of true positive predictions out of all positive predictions made by the model.
Predictive Analytics
Predictive analytics involves using historical data, statistical algorithms, and machine learning techniques to predict future outcomes. It is used in various domains such as finance, healthcare, and marketing.
Percentile
A percentile is a measure used in statistics indicating the value below which a given percentage of observations in a group of observations falls.
Q
Quantitative Data
Quantitative data refers to numerical data that can be measured and quantified. It is used in analysis of statistics for data science to identify patterns, trends, and relationships within the data.
Quantile
A quantile is a measure in statistics for data science that divides a dataset into equal-sized intervals. Common quantiles include quartiles (dividing data into four parts), percentiles (dividing data into 100 parts), and deciles (dividing data into ten parts).
Q-Learning
Q-Learning is a reinforcement learning algorithm that aims to find the optimal action-selection policy for an agent interacting with an environment. It uses a Q-value to estimate the expected future rewards for taking an action in a given state.
R
Random Forest
Random forest is an ensemble learning method that constructs multiple decision trees and combines their predictions to improve accuracy and reduce overfitting. It is widely used for classification and regression tasks.
Regression Analysis
Regression analysis is a technique in statistics for data science that is used to model the relationship between a dependent variable and one or more independent variables. It helps in predicting outcomes and identifying the strength of relationships between variables.
Reinforcement Learning
Reinforcement learning is a type of machine learning where an agent learns to make decisions by interacting with an environment and receiving feedback in the form of rewards or penalties. It is used in robotics, gaming, and autonomous systems.
Recall
Recall, also known as sensitivity, is a metric used to evaluate the performance of a classification model. It measures the proportion of actual positive cases that were correctly identified by the model.
S
Statistics
Statistics is a branch of mathematics dealing with the collection, analysis, interpretation, presentation, and organization of data. It provides tools and methods to make inferences and predictions based on data.
Supervised Learning
Supervised learning is a machine learning approach where the algorithm is trained on labeled data, with input-output pairs provided. It is used for tasks like classification and regression.
Support Vector Machine (SVM)
SVM is a classification algorithm that finds the optimal hyperplane separating different classes in the feature space. It is effective for high-dimensional data and complex boundaries.
SQL (Structured Query Language)
SQL is a programming language used to manage and manipulate relational databases. It allows data scientists to query, update, and manage data stored in databases.
Also read: 7 Best Data Science Books for Interview Preparation
T
Time Series Analysis
Time series analysis involves analyzing data points collected or recorded at specific time intervals. It is used in forecasting, trend analysis, and identifying seasonal patterns.
Tuning
Tuning involves optimizing the hyperparameters of a machine learning model to improve its performance. Techniques like grid search, random search, and Bayesian optimization are used for hyperparameter tuning.
U
Unsupervised Learning
Unsupervised learning is a machine learning approach where the algorithm is trained on unlabeled data, with no predefined output. It is used for tasks like clustering, anomaly detection, and dimensionality reduction.
Underfitting
Underfitting occurs when a machine learning model is too simple to capture the underlying patterns in the data, resulting in poor performance. It can be addressed by using more complex models or adding relevant features.
Uplift Modeling
Uplift modeling is a technique used to predict the incremental impact of an intervention or treatment. It is commonly used in marketing to identify customers who are likely to respond positively to a campaign.
V
Validation Set
A validation set is a subset of data used to evaluate the performance of a machine learning model during training. It helps in tuning hyperparameters and preventing overfitting.
Variance
Variance is a measure of the spread of data points around the mean. In machine learning, high variance indicates that a model is sensitive to small fluctuations in the training data, leading to overfitting.
Visualization
Visualization involves creating graphical representations of data to facilitate understanding and interpretation. Common visualization tools include matplotlib, seaborn, and Tableau.
W
Weight
In machine learning, weights are parameters that determine the importance of input features in a model. They are adjusted during training to minimize the loss function and improve model accuracy.
Word Embedding
Word embedding is a technique used in natural language processing to represent words as vectors in a continuous vector space. It captures semantic relationships between words and is used in tasks like word similarity and text classification.
Z
Z-Score
A Z-score is a statistical measure that indicates the number of standard deviations a data point is from the mean. It is used in standardizing data, outlier detection, and hypothesis testing.
Z-Test
A Z-test is a statistical test used to determine if there is a significant difference between the means of two populations. It is used in hypothesis testing when the sample size is large and the population variance is known.
Also read: How to Prepare for Data Engineer Interviews
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FAQs: Data Science Glossary
Q1. What is a Common Data Science Interview Question About Algorithms?
A common data science interview question is to explain the difference between supervised and unsupervised learning algorithms.
Q2. How Can I Prepare for Data Science Interview Questions on Big Data?
To prepare for data science interview questions on big data, review concepts like Hadoop, Spark, and the three V’s: volume, velocity, and variety.
Q3. What Types of Data Science Interview Questions Focus on Machine Learning?
Data science interview questions often focus on machine learning techniques such as classification, clustering, and regression analysis.
Q4. What Should I Know About Feature Engineering for Data Science Interview Questions?
For data science interview questions, understand how to create, select, and transform features to improve model performance.
Q5. How Can I Answer Data Science Interview Questions on Model Evaluation?
Be prepared to discuss metrics like accuracy, precision, recall, and F1 score to answer data science interview questions on model evaluation.
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