Advanced Data Science Concepts 🚀

1️⃣ Feature Engineering & Selection

Handling Missing Values – Imputation techniques (mean, median, KNN).

Encoding Categorical Variables – One-Hot Encoding, Label Encoding, Target Encoding.

Scaling & Normalization – StandardScaler, MinMaxScaler, RobustScaler.

Dimensionality Reduction – PCA, t-SNE, UMAP, LDA.


2️⃣ Machine Learning Optimization

Hyperparameter Tuning – Grid Search, Random Search, Bayesian Optimization.

Model Validation – Cross-validation, Bootstrapping.

Class Imbalance Handling – SMOTE, Oversampling, Undersampling.

Ensemble Learning – Bagging, Boosting (XGBoost, LightGBM, CatBoost), Stacking.


3️⃣ Deep Learning & Neural Networks

Neural Network Architectures – CNNs, RNNs, Transformers.

Activation Functions – ReLU, Sigmoid, Tanh, Softmax.

Optimization Algorithms – SGD, Adam, RMSprop.

Transfer Learning – Pre-trained models like BERT, GPT, ResNet.


4️⃣ Time Series Analysis

Forecasting Models – ARIMA, SARIMA, Prophet.

Feature Engineering for Time Series – Lag features, Rolling statistics.

Anomaly Detection – Isolation Forest, Autoencoders.


5️⃣ NLP (Natural Language Processing)

Text Preprocessing – Tokenization, Stemming, Lemmatization.

Word Embeddings – Word2Vec, GloVe, FastText.

Sequence Models – LSTMs, Transformers, BERT.

Text Classification & Sentiment Analysis – TF-IDF, Attention Mechanism.


6️⃣ Computer Vision

Image Processing – OpenCV, PIL.

Object Detection – YOLO, Faster R-CNN, SSD.

Image Segmentation – U-Net, Mask R-CNN.


7️⃣ Reinforcement Learning

Markov Decision Process (MDP) – Reward-based learning.

Q-Learning & Deep Q-Networks (DQN) – Policy improvement techniques.

Multi-Agent RL – Competitive and cooperative learning.


8️⃣ MLOps & Model Deployment

Model Monitoring & Versioning – MLflow, DVC.

Cloud ML Services – AWS SageMaker, GCP AI Platform.

API Deployment – Flask, FastAPI, TensorFlow Serving.


Like if you want detailed explanation on each topic ❤️

Data Science & Machine Learning Resources: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D

Hope this helps you 😊

Guys, We Did It!

We just crossed 1 Lakh followers on WhatsApp — and I’m dropping something massive for you all!

I’m launching a Data Science Learning Series — where I will cover essential Data Science & Machine Learning concepts from basic to advanced level covering real-world projects with step-by-step explanations, hands-on examples, and quizzes to test your skills after every major topic.

Here’s what we’ll cover in the coming days:

Week 1: Data Science Foundations

- What is Data Science?

- Where is DS used in real life?

- Data Analyst vs Data Scientist vs ML Engineer

- Tools used in DS (with icons & examples)

- DS Life Cycle (Step-by-step)

- Mini Quiz: Week 1 Topics

Week 2: Python for Data Science (Basics Only)

- Variables, Data Types, Lists, Dicts (with real-world data)

- Loops & Conditional Statements

- Functions (only basics)

- Importing CSV, Viewing Data

- Intro to Pandas DataFrame

- Mini Quiz: Python Topics


Week 3: Data Cleaning & Preparation

- Handling Missing Data

- Duplicates, Outliers (conceptual + pandas code)

- Data Type Conversions

- Renaming Columns, Reindexing

- Combining Datasets

- Mini Quiz: Choose the right method (dropna vs fillna, etc.)


Week 4: Data Exploration & Visualization

- Descriptive Stats (mean, median, std)

- GroupBy, Value_counts

- Visualizing with Pandas (plot, bar, hist)

- Matplotlib & Seaborn (basic use only)

- Correlation & Heatmaps

- Mini Quiz: Match chart type with goal


Week 5: Feature Engineering + Intro to ML

What is Feature Engineering?

Encoding (Label, One-Hot), Scaling

Train-Test Split, ML Pipeline

Supervised vs Unsupervised

Linear Regression: Concept Only

Mini Quiz: Regression or Classification?



Week 6: Model Building & Evaluation

- Train a Linear Regression Model

- Logistic Regression (basic example)

- Model Evaluation (Accuracy, Precision, Recall)

- Confusion Matrix (explanation)

- Overfitting & Underfitting (concepts)

- Mini Quiz: Model Evaluation Scenarios

Week 7: Real-World Projects

- Project 1: Predict House Prices

- Project 2: Classify Emails as Spam

- Project 3: Explore Titanic Dataset

- How to structure your project

- What to upload on GitHub

- Mini Quiz: What’s missing in this project?


Week 8: Career Boost Week

- Resume Tips for DS Roles

- Portfolio Tips (GitHub/Notion/PDF)

- Best Platforms to Apply (Internship + Job)

- 15 Most Common DS Interview Qs

- Mock Interview Questions for Practice

- Final Recap Quiz

React with ❤️ if you're ready for this new journey

Join our WhatsApp channel now: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D/998

Some useful PYTHON libraries for data science

NumPy stands for Numerical Python. The most powerful feature of NumPy is n-dimensional array. This library also contains basic linear algebra functions, Fourier transforms,  advanced random number capabilities and tools for integration with other low level languages like Fortran, C and C++

SciPy stands for Scientific Python. SciPy is built on NumPy. It is one of the most useful library for variety of high level science and engineering modules like discrete Fourier transform, Linear Algebra, Optimization and Sparse matrices.

Matplotlib for plotting vast variety of graphs, starting from histograms to line plots to heat plots.. You can use Pylab feature in ipython notebook (ipython notebook –pylab = inline) to use these plotting features inline. If you ignore the inline option, then pylab converts ipython environment to an environment, very similar to Matlab. You can also use Latex commands to add math to your plot.

Pandas for structured data operations and manipulations. It is extensively used for data munging and preparation. Pandas were added relatively recently to Python and have been instrumental in boosting Python’s usage in data scientist community.

Scikit Learn for machine learning. Built on NumPy, SciPy and matplotlib, this library contains a lot of efficient tools for machine learning and statistical modeling including classification, regression, clustering and dimensionality reduction.

Statsmodels for statistical modeling. Statsmodels is a Python module that allows users to explore data, estimate statistical models, and perform statistical tests. An extensive list of descriptive statistics, statistical tests, plotting functions, and result statistics are available for different types of data and each estimator.

Seaborn for statistical data visualization. Seaborn is a library for making attractive and informative statistical graphics in Python. It is based on matplotlib. Seaborn aims to make visualization a central part of exploring and understanding data.

Bokeh for creating interactive plots, dashboards and data applications on modern web-browsers. It empowers the user to generate elegant and concise graphics in the style of D3.js. Moreover, it has the capability of high-performance interactivity over very large or streaming datasets.

Blaze for extending the capability of Numpy and Pandas to distributed and streaming datasets. It can be used to access data from a multitude of sources including Bcolz, MongoDB, SQLAlchemy, Apache Spark, PyTables, etc. Together with Bokeh, Blaze can act as a very powerful tool for creating effective visualizations and dashboards on huge chunks of data.

Scrapy for web crawling. It is a very useful framework for getting specific patterns of data. It has the capability to start at a website home url and then dig through web-pages within the website to gather information.

SymPy for symbolic computation. It has wide-ranging capabilities from basic symbolic arithmetic to calculus, algebra, discrete mathematics and quantum physics. Another useful feature is the capability of formatting the result of the computations as LaTeX code.

Requests for accessing the web. It works similar to the the standard python library urllib2 but is much easier to code. You will find subtle differences with urllib2 but for beginners, Requests might be more convenient.

Additional libraries, you might need:

os for Operating system and file operations

networkx and igraph for graph based data manipulations

regular expressions for finding patterns in text data

BeautifulSoup for scrapping web. It is inferior to Scrapy as it will extract information from just a single webpage in a run.

Essential Data Science Concepts Everyone Should Know:

1. Data Types and Structures:

• Categorical: Nominal (unordered, e.g., colors) and Ordinal (ordered, e.g., education levels)

• Numerical: Discrete (countable, e.g., number of children) and Continuous (measurable, e.g., height)

• Data Structures: Arrays, Lists, Dictionaries, DataFrames (for organizing and manipulating data)

2. Descriptive Statistics:

• Measures of Central Tendency: Mean, Median, Mode (describing the typical value)

• Measures of Dispersion: Variance, Standard Deviation, Range (describing the spread of data)

• Visualizations: Histograms, Boxplots, Scatterplots (for understanding data distribution)

3. Probability and Statistics:

• Probability Distributions: Normal, Binomial, Poisson (modeling data patterns)

• Hypothesis Testing: Formulating and testing claims about data (e.g., A/B testing)

• Confidence Intervals: Estimating the range of plausible values for a population parameter

4. Machine Learning:

• Supervised Learning: Regression (predicting continuous values) and Classification (predicting categories)

• Unsupervised Learning: Clustering (grouping similar data points) and Dimensionality Reduction (simplifying data)

• Model Evaluation: Accuracy, Precision, Recall, F1-score (assessing model performance)

5. Data Cleaning and Preprocessing:

• Missing Value Handling: Imputation, Deletion (dealing with incomplete data)

• Outlier Detection and Removal: Identifying and addressing extreme values

• Feature Engineering: Creating new features from existing ones (e.g., combining variables)

6. Data Visualization:

• Types of Charts: Bar charts, Line charts, Pie charts, Heatmaps (for communicating insights visually)

• Principles of Effective Visualization: Clarity, Accuracy, Aesthetics (for conveying information effectively)

7. Ethical Considerations in Data Science:

• Data Privacy and Security: Protecting sensitive information

• Bias and Fairness: Ensuring algorithms are unbiased and fair

8. Programming Languages and Tools:

• Python: Popular for data science with libraries like NumPy, Pandas, Scikit-learn

• R: Statistical programming language with strong visualization capabilities

• SQL: For querying and manipulating data in databases

9. Big Data and Cloud Computing:

• Hadoop and Spark: Frameworks for processing massive datasets

• Cloud Platforms: AWS, Azure, Google Cloud (for storing and analyzing data)

10. Domain Expertise:

• Understanding the Data: Knowing the context and meaning of data is crucial for effective analysis

• Problem Framing: Defining the right questions and objectives for data-driven decision making

Bonus:

• Data Storytelling: Communicating insights and findings in a clear and engaging manner

Best Data Science & Machine Learning Resources: https://topmate.io/coding/914624

ENJOY LEARNING 👍👍

This post is for beginners who decided to learn Data Science. I want to tell you that becoming a data scientist is a journey (6 months - 1 year at least) and not a 1 month thing where u do some courses and you are a data scientist. There are different fields in Data Science that you have to first get familiar and strong in basics as well as do hands-on to get the abilities that are required to function in a full time job opportunity. Then further delve into advanced implementations.

There are plenty of roadmaps and online content both paid and free that you can follow. In a nutshell. A few essential things that will be necessary and in no particular order that will at least get your data science journey started are below:

Basic Statistics, Linear Algebra, calculus, probability
Programming language (R or Python) - Preferably Python if you rather want to later on move into a developer role instead of sticking to data science.
Machine Learning - All of the above will be used here to implement machine learning concepts.
Data Visualisation - again it could be simple excel or via r/python libraries or tools like Tableau,PowerBI etc.

This can be overwhelming but again its just an indication of what lies ahead. So most important thing is to just START instead of just contemplating the best way to go about this. Since lot of things can be learnt independently as well in no particular order.

You can use the below Sources to prepare your own roadmap:
@free4unow_backup - some free courses from here
@datasciencefun - check & search in this channel with #freecourses

Data Science - https://365datascience.pxf.io/q4m66g
Python - https://bit.ly/45rlWZE
Kaggle - https://www.kaggle.com/learn

A-Z of Data Science Part-1

A-Z of Data Science Part-2

If you want to Excel in Data Science and become an expert, master these essential concepts:

Core Data Science Skills:

• Python for Data Science – Pandas, NumPy, Matplotlib, Seaborn
• SQL for Data Extraction – SELECT, JOIN, GROUP BY, CTEs, Window Functions
• Data Cleaning & Preprocessing – Handling missing data, outliers, duplicates
• Exploratory Data Analysis (EDA) – Visualizing data trends

Machine Learning (ML):

• Supervised Learning – Linear Regression, Decision Trees, Random Forest
• Unsupervised Learning – Clustering, PCA, Anomaly Detection
• Model Evaluation – Cross-validation, Confusion Matrix, ROC-AUC
• Hyperparameter Tuning – Grid Search, Random Search

Deep Learning (DL):

• Neural Networks – TensorFlow, PyTorch, Keras
• CNNs & RNNs – Image & sequential data processing
• Transformers & LLMs – GPT, BERT, Stable Diffusion

Big Data & Cloud Computing:

• Hadoop & Spark – Handling large datasets
• AWS, GCP, Azure – Cloud-based data science solutions
• MLOps – Deploy models using Flask, FastAPI, Docker

Statistics & Mathematics for Data Science:

• Probability & Hypothesis Testing – P-values, T-tests, Chi-square
• Linear Algebra & Calculus – Matrices, Vectors, Derivatives
• Time Series Analysis – ARIMA, Prophet, LSTMs

Real-World Applications:

• Recommendation Systems – Personalized AI suggestions
• NLP (Natural Language Processing) – Sentiment Analysis, Chatbots
• AI-Powered Business Insights – Data-driven decision-making

Like this post if you need a complete tutorial on essential data science topics! 👍❤️

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5 Algorithms you must know as a data scientist 👩‍💻 🧑‍💻

1. Dimensionality Reduction
- PCA, t-SNE, LDA

2. Regression models
- Linesr regression, Kernel-based regression models, Lasso Regression, Ridge regression, Elastic-net regression

3. Classification models
- Binary classification- Logistic regression, SVM
- Multiclass classification- One versus one, one versus many
- Multilabel classification

4. Clustering models
- K Means clustering, Hierarchical clustering, DBSCAN, BIRCH models

5. Decision tree based models
- CART model, ensemble models(XGBoost, LightGBM, CatBoost)

Best Data Science & Machine Learning Resources: https://topmate.io/coding/914624

Join our WhatsApp channel: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D

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Projects to boost your resume for data roles

🚀 Complete Roadmap to Become a Data Scientist in 5 Months

📅 Week 1-2: Fundamentals
✅ Day 1-3: Introduction to Data Science, its applications, and roles.
✅ Day 4-7: Brush up on Python programming 🐍.
✅ Day 8-10: Learn basic statistics 📊 and probability 🎲.

🔍 Week 3-4: Data Manipulation & Visualization
📝 Day 11-15: Master Pandas for data manipulation.
📈 Day 16-20: Learn Matplotlib & Seaborn for data visualization.

🤖 Week 5-6: Machine Learning Foundations
🔬 Day 21-25: Introduction to scikit-learn.
📊 Day 26-30: Learn Linear & Logistic Regression.

🏗 Week 7-8: Advanced Machine Learning
🌳 Day 31-35: Explore Decision Trees & Random Forests.
📌 Day 36-40: Learn Clustering (K-Means, DBSCAN) & Dimensionality Reduction.

🧠 Week 9-10: Deep Learning
🤖 Day 41-45: Basics of Neural Networks with TensorFlow/Keras.
📸 Day 46-50: Learn CNNs & RNNs for image & text data.

🏛 Week 11-12: Data Engineering
🗄 Day 51-55: Learn SQL & Databases.
🧹 Day 56-60: Data Preprocessing & Cleaning.

📊 Week 13-14: Model Evaluation & Optimization
📏 Day 61-65: Learn Cross-validation & Hyperparameter Tuning.
📉 Day 66-70: Understand Evaluation Metrics (Accuracy, Precision, Recall, F1-score).

🏗 Week 15-16: Big Data & Tools
🐘 Day 71-75: Introduction to Big Data Technologies (Hadoop, Spark).
☁️ Day 76-80: Learn Cloud Computing (AWS, GCP, Azure).

🚀 Week 17-18: Deployment & Production
🛠 Day 81-85: Deploy models using Flask or FastAPI.
📦 Day 86-90: Learn Docker & Cloud Deployment (AWS, Heroku).

🎯 Week 19-20: Specialization
📝 Day 91-95: Choose NLP or Computer Vision, based on your interest.

🏆 Week 21-22: Projects & Portfolio
📂 Day 96-100: Work on Personal Data Science Projects.

💬 Week 23-24: Soft Skills & Networking
🎤 Day 101-105: Improve Communication & Presentation Skills.
🌐 Day 106-110: Attend Online Meetups & Forums.

🎯 Week 25-26: Interview Preparation
💻 Day 111-115: Practice Coding Interviews (LeetCode, HackerRank).
📂 Day 116-120: Review your projects & prepare for discussions.

👨‍💻 Week 27-28: Apply for Jobs
📩 Day 121-125: Start applying for Entry-Level Data Scientist positions.

🎤 Week 29-30: Interviews
📝 Day 126-130: Attend Interviews & Practice Whiteboard Problems.

🔄 Week 31-32: Continuous Learning
📰 Day 131-135: Stay updated with the Latest Data Science Trends.

🏆 Week 33-34: Accepting Offers
📝 Day 136-140: Evaluate job offers & Negotiate Your Salary.

🏢 Week 35-36: Settling In
🎯 Day 141-150: Start your New Data Science Job, adapt & keep learning!

🎉 Enjoy Learning & Build Your Dream Career in Data Science! 🚀🔥

Amazon Interview Process for Data Scientist position

📍Round 1- Phone Screen round
This was a preliminary round to check my capability, projects to coding, Stats, ML, etc.

After clearing this round the technical Interview rounds started. There were 5-6 rounds (Multiple rounds in one day).

📍 𝗥𝗼𝘂𝗻𝗱 𝟮- 𝗗𝗮𝘁𝗮 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗕𝗿𝗲𝗮𝗱𝘁𝗵:
In this round the interviewer tested my knowledge on different kinds of topics.

📍𝗥𝗼𝘂𝗻𝗱 𝟯- 𝗗𝗲𝗽𝘁𝗵 𝗥𝗼𝘂𝗻𝗱:
In this round the interviewers grilled deeper into 1-2 topics. I was asked questions around:
Standard ML tech, Linear Equation, Techniques, etc.

📍𝗥𝗼𝘂𝗻𝗱 𝟰- 𝗖𝗼𝗱𝗶𝗻𝗴 𝗥𝗼𝘂𝗻𝗱-
This was a Python coding round, which I cleared successfully.

📍𝗥𝗼𝘂𝗻𝗱 𝟱- This was 𝗛𝗶𝗿𝗶𝗻𝗴 𝗠𝗮𝗻𝗮𝗴𝗲𝗿 where my fitment for the team got assessed.

📍𝗟𝗮𝘀𝘁 𝗥𝗼𝘂𝗻𝗱- 𝗕𝗮𝗿 𝗥𝗮𝗶𝘀𝗲𝗿- Very important round, I was asked heavily around Leadership principles & Employee dignity questions.

So, here are my Tips if you’re targeting any Data Science role:
-> Never make up stuff & don’t lie in your Resume.
-> Projects thoroughly study.
-> Practice SQL, DSA, Coding problem on Leetcode/Hackerank.
-> Download data from Kaggle & build EDA (Data manipulation questions are asked)

Best Data Science & Machine Learning Resources: https://topmate.io/coding/914624

ENJOY LEARNING 👍👍

Guys, Big Announcement!

We’ve officially hit 5 Lakh followers on WhatsApp and it’s time to level up together! ❤️

I've launched a Python Learning Series — designed for beginners to those preparing for technical interviews or building real-world projects.

This will be a step-by-step journey — from basics to advanced — with real examples and short quizzes after each topic to help you lock in the concepts.

Here’s what we’ll cover in the coming days:

Week 1: Python Fundamentals

- Variables & Data Types

- Operators & Expressions

- Conditional Statements (if, elif, else)

- Loops (for, while)

- Functions & Parameters

- Input/Output & Basic Formatting


Week 2: Core Python Skills

- Lists, Tuples, Sets, Dictionaries

- String Manipulation

- List Comprehensions

- File Handling

- Exception Handling


Week 3: Intermediate Python

- Lambda Functions

- Map, Filter, Reduce

- Modules & Packages

- Scope & Global Variables

- Working with Dates & Time


Week 4: OOP & Pythonic Concepts

- Classes & Objects

- Inheritance & Polymorphism

- Decorators (Intro level)

- Generators & Iterators

- Writing Clean & Readable Code


Week 5: Real-World & Interview Prep

- Web Scraping (BeautifulSoup)

- Working with APIs (Requests)

- Automating Tasks

- Data Analysis Basics (Pandas)

- Interview Coding Patterns

You can join our WhatsApp channel to access it for free: https://whatsapp.com/channel/0029VaiM08SDuMRaGKd9Wv0L/1527

Some important questions to crack data science interview

Q. Describe how Gradient Boosting works.

A. Gradient boosting is a type of machine learning boosting. It relies on the intuition that the best possible next model, when combined with previous models, minimizes the overall prediction error. If a small change in the prediction for a case causes no change in error, then next target outcome of the case is zero. Gradient boosting produces a prediction model in the form of an ensemble of weak prediction models, typically decision trees.


Q. Describe the decision tree model.

A. Decision Trees are a type of Supervised Machine Learning where the data is continuously split according to a certain parameter. The leaves are the decisions or the final outcomes. A decision tree is a machine learning algorithm that partitions the data into subsets.


Q. What is a neural network?

A. Neural networks are a set of algorithms, modeled loosely after the human brain, that are designed to recognize patterns. They interpret sensory data through a kind of machine perception, labeling or clustering raw input. They, also known as Artificial Neural Networks, are the subset of Deep Learning.


Q. Explain the Bias-Variance Tradeoff

A. The bias–variance tradeoff is the property of a model that the variance of the parameter estimated across samples can be reduced by increasing the bias in the estimated parameters.


Q. What’s the difference between L1 and L2 regularization?

A. The main intuitive difference between the L1 and L2 regularization is that L1 regularization tries to estimate the median of the data while the L2 regularization tries to estimate the mean of the data to avoid overfitting. That value will also be the median of the data distribution mathematically.

ENJOY LEARNING 👍👍

Today, lets understand Machine Learning in simplest way possible

What is Machine Learning?

Think of it like this:

Machine Learning is when you teach a computer to learn from data, so it can make decisions or predictions without being told exactly what to do step-by-step.

Real-Life Example:
Let’s say you want to teach a kid how to recognize a dog.
You show the kid a bunch of pictures of dogs.

The kid starts noticing patterns — “Oh, they have four legs, fur, floppy ears...”

Next time the kid sees a new picture, they might say, “That’s a dog!” — even if they’ve never seen that exact dog before.

That’s what machine learning does — but instead of a kid, it's a computer.

In Tech Terms (Still Simple):

You give the computer data (like pictures, numbers, or text).
You give it examples of the right answers (like “this is a dog”, “this is not a dog”).
It learns the patterns.

Later, when you give it new data, it makes a smart guess.

Few Common Uses of ML You See Every Day:

Netflix: Suggesting shows you might like.
Google Maps: Predicting traffic.
Amazon: Recommending products.
Banks: Detecting fraud in transactions.

I have curated the best interview resources to crack Data Science Interviews
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Data Science Learning Plan

Step 1: Mathematics for Data Science (Statistics, Probability, Linear Algebra)

Step 2: Python for Data Science (Basics and Libraries)

Step 3: Data Manipulation and Analysis (Pandas, NumPy)

Step 4: Data Visualization (Matplotlib, Seaborn, Plotly)

Step 5: Databases and SQL for Data Retrieval

Step 6: Introduction to Machine Learning (Supervised and Unsupervised Learning)

Step 7: Data Cleaning and Preprocessing

Step 8: Feature Engineering and Selection

Step 9: Model Evaluation and Tuning

Step 10: Deep Learning (Neural Networks, TensorFlow, Keras)

Step 11: Working with Big Data (Hadoop, Spark)

Step 12: Building Data Science Projects and Portfolio

Data Science Resources
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Various types of test used in statistics for data science

T-test: used to test whether the means of two groups are significantly different from each other.

ANOVA: used to test whether the means of three or more groups are significantly different from each other.

Chi-squared test: used to test whether two categorical variables are independent or associated with each other.

Pearson correlation test: used to test whether there is a significant linear relationship between two continuous variables.

Wilcoxon signed-rank test: used to test whether the median of two related samples is significantly different from each other.

Mann-Whitney U test: used to test whether the median of two independent samples is significantly different from each other.

Kruskal-Wallis test: used to test whether the medians of three or more independent samples are significantly different from each other.

Friedman test: used to test whether the medians of three or more related samples are significantly different from each other.

Machine Learning Algorithms every data scientist should know:

📌 Supervised Learning:

🔹 Regression
∟ Linear Regression
∟ Ridge & Lasso Regression
∟ Polynomial Regression

🔹 Classification
∟ Logistic Regression
∟ K-Nearest Neighbors (KNN)
∟ Decision Tree
∟ Random Forest
∟ Support Vector Machine (SVM)
∟ Naive Bayes
∟ Gradient Boosting (XGBoost, LightGBM, CatBoost)


📌 Unsupervised Learning:

🔹 Clustering
∟ K-Means
∟ Hierarchical Clustering
∟ DBSCAN

🔹 Dimensionality Reduction
∟ PCA (Principal Component Analysis)
∟ t-SNE
∟ LDA (Linear Discriminant Analysis)


📌 Reinforcement Learning (Basics):
∟ Q-Learning
∟ Deep Q Network (DQN)


📌 Ensemble Techniques:
∟ Bagging (Random Forest)
∟ Boosting (XGBoost, AdaBoost, Gradient Boosting)
∟ Stacking

Don’t forget to learn model evaluation metrics: accuracy, precision, recall, F1-score, AUC-ROC, confusion matrix, etc.

Free Machine Learning Resources: https://whatsapp.com/channel/0029Va8v3eo1NCrQfGMseL2D

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Here are some essential data science concepts from A to Z:

A - Algorithm: A set of rules or instructions used to solve a problem or perform a task in data science.

B - Big Data: Large and complex datasets that cannot be easily processed using traditional data processing applications.

C - Clustering: A technique used to group similar data points together based on certain characteristics.

D - Data Cleaning: The process of identifying and correcting errors or inconsistencies in a dataset.

E - Exploratory Data Analysis (EDA): The process of analyzing and visualizing data to understand its underlying patterns and relationships.

F - Feature Engineering: The process of creating new features or variables from existing data to improve model performance.

G - Gradient Descent: An optimization algorithm used to minimize the error of a model by adjusting its parameters.

H - Hypothesis Testing: A statistical technique used to test the validity of a hypothesis or claim based on sample data.

I - Imputation: The process of filling in missing values in a dataset using statistical methods.

J - Joint Probability: The probability of two or more events occurring together.

K - K-Means Clustering: A popular clustering algorithm that partitions data into K clusters based on similarity.

L - Linear Regression: A statistical method used to model the relationship between a dependent variable and one or more independent variables.

M - Machine Learning: A subset of artificial intelligence that uses algorithms to learn patterns and make predictions from data.

N - Normal Distribution: A symmetrical bell-shaped distribution that is commonly used in statistical analysis.

O - Outlier Detection: The process of identifying and removing data points that are significantly different from the rest of the dataset.

P - Precision and Recall: Evaluation metrics used to assess the performance of classification models.

Q - Quantitative Analysis: The process of analyzing numerical data to draw conclusions and make decisions.

R - Random Forest: An ensemble learning algorithm that builds multiple decision trees to improve prediction accuracy.

S - Support Vector Machine (SVM): A supervised learning algorithm used for classification and regression tasks.

T - Time Series Analysis: A statistical technique used to analyze and forecast time-dependent data.

U - Unsupervised Learning: A type of machine learning where the model learns patterns and relationships in data without labeled outputs.

V - Validation Set: A subset of data used to evaluate the performance of a model during training.

W - Web Scraping: The process of extracting data from websites for analysis and visualization.

X - XGBoost: An optimized gradient boosting algorithm that is widely used in machine learning competitions.

Y - Yield Curve Analysis: The study of the relationship between interest rates and the maturity of fixed-income securities.

Z - Z-Score: A standardized score that represents the number of standard deviations a data point is from the mean.

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Data Science Interview Questions with Answers

Q. Explain the data preprocessing steps in data analysis.

Ans. Data preprocessing transforms the data into a format that is more easily and effectively processed in data mining, machine learning and other data science tasks.
1. Data profiling.
2. Data cleansing.
3. Data reduction.
4. Data transformation.
5. Data enrichment.
6. Data validation.

Q. What Are the Three Stages of Building a Model in Machine Learning?

Ans. The three stages of building a machine learning model are:

Model Building: Choosing a suitable algorithm for the model and train it according to the requirement

Model Testing: Checking the accuracy of the model through the test data

Applying the Model: Making the required changes after testing and use the final model for real-time projects


Q. What are the subsets of SQL?

Ans. The following are the four significant subsets of the SQL:

Data definition language (DDL): It defines the data structure that consists of commands like CREATE, ALTER, DROP, etc.

Data manipulation language (DML): It is used to manipulate existing data in the database. The commands in this category are SELECT, UPDATE, INSERT, etc.

Data control language (DCL): It controls access to the data stored in the database. The commands in this category include GRANT and REVOKE.

Transaction Control Language (TCL): It is used to deal with the transaction operations in the database. The commands in this category are COMMIT, ROLLBACK, SET TRANSACTION, SAVEPOINT, etc.


Q. What is a Parameter in Tableau? Give an Example.

Ans. A parameter is a dynamic value that a customer could select, and you can use it to replace constant values in calculations, filters, and reference lines.
For example, when creating a filter to show the top 10 products based on total profit instead of the fixed value, you can update the filter to show the top 10, 20, or 30 products using a parameter.

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