Important Python Functions ✅

Python Commands Cheatsheet ✅

Core data science concepts you should know:

🔢 1. Statistics & Probability

Descriptive statistics: Mean, median, mode, standard deviation, variance

Inferential statistics: Hypothesis testing, confidence intervals, p-values, t-tests, ANOVA

Probability distributions: Normal, Binomial, Poisson, Uniform

Bayes' Theorem

Central Limit Theorem


📊 2. Data Wrangling & Cleaning

Handling missing values

Outlier detection and treatment

Data transformation (scaling, encoding, normalization)

Feature engineering

Dealing with imbalanced data


📈 3. Exploratory Data Analysis (EDA)

Univariate, bivariate, and multivariate analysis

Correlation and covariance

Data visualization tools: Matplotlib, Seaborn, Plotly

Insights generation through visual storytelling


🤖 4. Machine Learning Fundamentals

Supervised Learning: Linear regression, logistic regression, decision trees, SVM, k-NN

Unsupervised Learning: K-means, hierarchical clustering, PCA

Model evaluation: Accuracy, precision, recall, F1-score, ROC-AUC

Cross-validation and overfitting/underfitting

Bias-variance tradeoff


🧠 5. Deep Learning (Basics)

Neural networks: Perceptron, MLP

Activation functions (ReLU, Sigmoid, Tanh)

Backpropagation

Gradient descent and learning rate

CNNs and RNNs (intro level)


🗃️ 6. Data Structures & Algorithms (DSA)

Arrays, lists, dictionaries, sets

Sorting and searching algorithms

Time and space complexity (Big-O notation)

Common problems: string manipulation, matrix operations, recursion


💾 7. SQL & Databases

SELECT, WHERE, GROUP BY, HAVING

JOINS (inner, left, right, full)

Subqueries and CTEs

Window functions

Indexing and normalization


📦 8. Tools & Libraries

Python: pandas, NumPy, scikit-learn, TensorFlow, PyTorch

R: dplyr, ggplot2, caret

Jupyter Notebooks for experimentation

Git and GitHub for version control


🧪 9. A/B Testing & Experimentation

Control vs. treatment group

Hypothesis formulation

Significance level, p-value interpretation

Power analysis


🌐 10. Business Acumen & Storytelling

Translating data insights into business value

Crafting narratives with data

Building dashboards (Power BI, Tableau)

Knowing KPIs and business metrics

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Data Analytics Interview Questions

1. What is the difference between SQL and MySQL?

SQL is a standard language for retrieving and manipulating structured databases. On the contrary, MySQL is a relational database management system, like SQL Server, Oracle or IBM DB2, that is used to manage SQL databases.


2. What is a Cross-Join?

Cross join can be defined as a cartesian product of the two tables included in the join. The table after join contains the same number of rows as in the cross-product of the number of rows in the two tables. If a WHERE clause is used in cross join then the query will work like an INNER JOIN.


3. What is a Stored Procedure?

A stored procedure is a subroutine available to applications that access a relational database management system (RDBMS). Such procedures are stored in the database data dictionary. The sole disadvantage of stored procedure is that it can be executed nowhere except in the database and occupies more memory in the database server.


4. What is Pattern Matching in SQL?

SQL pattern matching provides for pattern search in data if you have no clue as to what that word should be. This kind of SQL query uses wildcards to match a string pattern, rather than writing the exact word. The LIKE operator is used in conjunction with SQL Wildcards to fetch the required information.

10 powerful lessons:

1. Embrace Writing to Clear Your Mind
↳ Writing down your thoughts and ideas can help you clarify and organize your thoughts.
↳ Write out your goals and plans to enhance focus and motivation.

2. Always Aim for the Stars
↳ Set ambitious goals that challenge you to grow and learn.
↳ Surround yourself with people who inspire and push you to be your best.

3. Great Leaders Put Others First
↳ Great leaders focus on their team's success, not just their own.
↳ Leadership is not about personal gain, but about positively impacting others.

4. The Power of Task Segmentation
↳ Breaking large tasks into smaller ones can help you feel less overwhelmed and more focused.
↳ Smaller tasks are easier to complete, which can help you build momentum and stay motivated.


5. Reframing Challenges
↳ Embrace challenges as opportunities to learn and grow.
↳ Reflect on failures to identify areas for improvement.

6. Leadership is About Service, Not Power
↳ Leadership is about empowering others to be their best selves.
↳ Great leaders inspire others to innovate and think creatively.

7. The Power of Pen and Paper
↳ Writing helps you understand your own thoughts better.
↳ Write out your thoughts and feelings to gain perspective and clarity.

8. Master the Power of Active Listening
↳ Focus on what others are saying, not on your reply.
↳ Avoid interrupting or formulating your response while the other person is speaking.

9. Writing Sharpens Your Thoughts
↳ Writing forces you to organize your thoughts.
↳ Seeing ideas on paper helps you spot flaws and improvements.

10. Embrace Discipline for Lasting Success
↳ Discipline is choosing between what you want now and what you want most.
↳ Small, consistent actions lead to big results over time.

10 simple yet transformative lessons to shift your mindset.

Roadmap to Become a Data Analyst:

📊 Learn Excel & Google Sheets (Formulas, Pivot Tables)
∟📊 Master SQL (SELECT, JOINs, CTEs, Window Functions)
∟📊 Learn Data Visualization (Power BI / Tableau)
∟📊 Understand Statistics & Probability
∟📊 Learn Python (Pandas, NumPy, Matplotlib, Seaborn)
∟📊 Work with Real Datasets (Kaggle / Public APIs)
∟📊 Learn Data Cleaning & Preprocessing Techniques
∟📊 Build Case Studies & Projects
∟📊 Create Portfolio & Resume
∟✅ Apply for Internships / Jobs

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📚👀🚀Preparing for a Data science/ Data Analytics interview can be challenging, but with the right strategy, you can enhance your chances of success. Here are some key tips to assist you in getting ready:

Review Fundamental Concepts: Ensure you have a strong grasp of statistics, probability, linear algebra, data structures, algorithms, and programming languages like Python, R, and SQL.

Refresh Machine Learning Knowledge: Familiarize yourself with various machine learning algorithms, including supervised, unsupervised, and reinforcement learning.

Practice Coding: Sharpen your coding skills by solving data science-related problems on platforms like HackerRank, LeetCode, and Kaggle.

Build a Project Portfolio: Showcase your proficiency by creating a portfolio highlighting projects covering data cleaning, wrangling, exploratory data analysis, and machine learning.

Hone Communication Skills: Practice articulating complex technical ideas in simple terms, as effective communication is vital for data scientists when interacting with non-technical stakeholders.

Research the Company: Gain insights into the company's operations, industry, and how they leverage data to solve challenges.

🧠👍By adhering to these guidelines, you'll be well-prepared for your upcoming data science interview. Best of luck!

Hope this helps 👍❤️:⁠-⁠)

Being a Generalist Data Scientist won't get you hired.
Here is how you can specialize 👇

Companies have specific problems that require certain skills to solve. If you do not know which path you want to follow. Start broad first, explore your options, then specialize.

To discover what you enjoy the most, try answering different questions for each DS role:


- 𝐌𝐚𝐜𝐡𝐢𝐧𝐞 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫
Qs:
“How should we monitor model performance in production?”

- 𝐃𝐚𝐭𝐚 𝐀𝐧𝐚𝐥𝐲𝐬𝐭 / 𝐏𝐫𝐨𝐝𝐮𝐜𝐭 𝐃𝐚𝐭𝐚 𝐒𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭
Qs:
“How can we visualize customer segmentation to highlight key demographics?”

- 𝐃𝐚𝐭𝐚 𝐒𝐜𝐢𝐞𝐧𝐭𝐢𝐬𝐭
Qs:
“How can we use clustering to identify new customer segments for targeted marketing?”

- 𝐌𝐚𝐜𝐡𝐢𝐧𝐞 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠 𝐑𝐞𝐬𝐞𝐚𝐫𝐜𝐡𝐞𝐫
Qs:
“What novel architectures can we explore to improve model robustness?”

- 𝐌𝐋𝐎𝐩𝐬 𝐄𝐧𝐠𝐢𝐧𝐞𝐞𝐫
Qs:
“How can we automate the deployment of machine learning models to ensure continuous integration and delivery?”

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

ENJOY LEARNING 👍👍

Data Storytelling

Data Science Techniques

SQL Interview Questions with Answers

1. How to change a table name in SQL?
This is the command to change a table name in SQL:
ALTER TABLE table_name
RENAME TO new_table_name;
We will start off by giving the keywords ALTER TABLE, then we will follow it up by giving the original name of the table, after that, we will give in the keywords RENAME TO and finally, we will give the new table name.

2. How to use LIKE in SQL?
The LIKE operator checks if an attribute value matches a given string pattern. Here is an example of LIKE operator
SELECT * FROM employees WHERE first_name like ‘Steven’;
With this command, we will be able to extract all the records where the first name is like “Steven”.

3. If we drop a table, does it also drop related objects like constraints, indexes, columns, default, views and sorted procedures?
Yes, SQL server drops all related objects, which exists inside a table like constraints, indexes, columns, defaults etc. But dropping a table will not drop views and sorted procedures as they exist outside the table.

4. Explain SQL Constraints.
SQL Constraints are used to specify the rules of data type in a table. They can be specified while creating and altering the table. The following are the constraints in SQL: NOT NULL CHECK DEFAULT UNIQUE PRIMARY KEY FOREIGN KEY

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