Data Analytics & AI | SQL Interviews | Power BI Resources
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๐Ÿ”“Explore the fascinating world of Data Analytics & Artificial Intelligence

๐Ÿ’ป Best AI tools, free resources, and expert advice to land your dream tech job.

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Data Analytics Interview Topics in structured way :

๐Ÿ”ตPython: Data Structures: Lists, tuples, dictionaries, sets Pandas: Data manipulation (DataFrame operations, merging, reshaping) NumPy: Numeric computing, arrays Visualization: Matplotlib, Seaborn for creating charts

๐Ÿ”ตSQL: Basic : SELECT, WHERE, JOIN, GROUP BY, ORDER BY Advanced : Subqueries, nested queries, window functions DBMS: Creating tables, altering schema, indexing Joins: Inner join, outer join, left/right join Data Manipulation: UPDATE, DELETE, INSERT statements Aggregate Functions: SUM, AVG, COUNT, MAX, MIN

๐Ÿ”ตExcel: Formulas & Functions: VLOOKUP, HLOOKUP, IF, SUMIF, COUNTIF Data Cleaning: Removing duplicates, handling errors, text-to-columns PivotTables Charts and Graphs What-If Analysis: Scenario Manager, Goal Seek, Solver

๐Ÿ”ตPower BI:
Data Modeling: Creating relationships between datasets
Transformation: Cleaning & shaping data using
Power Query Editor Visualization: Creating interactive reports and dashboards
DAX (Data Analysis Expressions): Formulas for calculated columns, measures Publishing and sharing reports, scheduling data refresh

๐Ÿ”ต Statistics Fundamentals: Mean, median, mode Variance, standard deviation Probability distributions Hypothesis testing, p-values, confidence intervals

๐Ÿ”ตData Manipulation and Cleaning: Data preprocessing techniques (handling missing values, outliers), Data normalization and standardization Data transformation Handling categorical data

๐Ÿ”ตData Visualization: Chart types (bar, line, scatter, histogram, boxplot) Data visualization libraries (matplotlib, seaborn, ggplot) Effective data storytelling through visualization

Also showcase these skills using data portfolio if possible

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Common Requirements for data analyst role ๐Ÿ‘‡

๐Ÿ‘‰ Must be proficient in writing complex SQL Queries.

๐Ÿ‘‰ Understand business requirements in BI context and design data models to transform raw data into meaningful insights.

๐Ÿ‘‰ Connecting data sources, importing data, and transforming data for Business intelligence.

๐Ÿ‘‰ Strong working knowledge in Excel and visualization tools like PowerBI, Tableau or QlikView

๐Ÿ‘‰ Developing visual reports, KPI scorecards, and dashboards using Power BI desktop.

Nowadays, recruiters primary focus on SQL & BI skills for data analyst roles. So try practicing SQL & create some BI projects using Tableau or Power BI.

*Here are some essential WhatsApp Channels with important resources:*

โฏ Jobs โžŸ https://whatsapp.com/channel/0029Vaxjq5a4dTnKNrdeiZ0J

โฏ SQL โžŸ https://whatsapp.com/channel/0029VanC5rODzgT6TiTGoa1v

โฏ Power BI โžŸ https://whatsapp.com/channel/0029Vai1xKf1dAvuk6s1v22c

โฏ Data Analysts โžŸ https://whatsapp.com/channel/0029VaGgzAk72WTmQFERKh02

โฏ Python โžŸ https://whatsapp.com/channel/0029VaiM08SDuMRaGKd9Wv0L

I am planning to come up with interview series as well to share some essential questions based on my experience in data analytics field.

Like this post if you want me to start the interview series ๐Ÿ‘โค๏ธ

Hope it helps :)
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How to master Python from scratch๐Ÿš€

1. Setup and Basics ๐Ÿ
   - Install Python ๐Ÿ–ฅ๏ธ: Download Python and set it up.
   - Hello, World! ๐ŸŒ: Write your first Hello World program.

2. Basic Syntax ๐Ÿ“œ
   - Variables and Data Types ๐Ÿ“Š: Learn about strings, integers, floats, and booleans.
   - Control Structures ๐Ÿ”„: Understand if-else statements, for loops, and while loops.
   - Functions ๐Ÿ› ๏ธ: Write reusable blocks of code.

3. Data Structures ๐Ÿ“‚
   - Lists ๐Ÿ“‹: Manage collections of items.
   - Dictionaries ๐Ÿ“–: Store key-value pairs.
   - Tuples ๐Ÿ“ฆ: Work with immutable sequences.
   - Sets ๐Ÿ”ข: Handle collections of unique items.

4. Modules and Packages ๐Ÿ“ฆ
   - Standard Library ๐Ÿ“š: Explore built-in modules.
   - Third-Party Packages ๐ŸŒ: Install and use packages with pip.

5. File Handling ๐Ÿ“
   - Read and Write Files ๐Ÿ“
   - CSV and JSON ๐Ÿ“‘

6. Object-Oriented Programming ๐Ÿงฉ
   - Classes and Objects ๐Ÿ›๏ธ
   - Inheritance and Polymorphism ๐Ÿ‘จโ€๐Ÿ‘ฉโ€๐Ÿ‘ง

7. Web Development ๐ŸŒ
   - Flask ๐Ÿผ: Start with a micro web framework.
   - Django ๐Ÿฆ„: Dive into a full-fledged web framework.

8. Data Science and Machine Learning ๐Ÿง 
   - NumPy ๐Ÿ“Š: Numerical operations.
   - Pandas ๐Ÿผ: Data manipulation and analysis.
   - Matplotlib ๐Ÿ“ˆ and Seaborn ๐Ÿ“Š: Data visualization.
   - Scikit-learn ๐Ÿค–: Machine learning.

9. Automation and Scripting ๐Ÿค–
   - Automate Tasks ๐Ÿ› ๏ธ: Use Python to automate repetitive tasks.
   - APIs ๐ŸŒ: Interact with web services.

10. Testing and Debugging ๐Ÿž
    - Unit Testing ๐Ÿงช: Write tests for your code.
    - Debugging ๐Ÿ”: Learn to debug efficiently.

11. Advanced Topics ๐Ÿš€
    - Concurrency and Parallelism ๐Ÿ•’
    - Decorators ๐ŸŒ€ and Generators โš™๏ธ
    - Web Scraping ๐Ÿ•ธ๏ธ: Extract data from websites using BeautifulSoup and Scrapy.

12. Practice Projects ๐Ÿ’ก
    - Calculator ๐Ÿงฎ
    - To-Do List App ๐Ÿ“‹
    - Weather App โ˜€๏ธ
    - Personal Blog ๐Ÿ“

13. Community and Collaboration ๐Ÿค
    - Contribute to Open Source ๐ŸŒ
    - Join Coding Communities ๐Ÿ’ฌ
    - Participate in Hackathons ๐Ÿ†

14. Keep Learning and Improving ๐Ÿ“ˆ
    - Read Books ๐Ÿ“–: Like "Automate the Boring Stuff with Python".
    - Watch Tutorials ๐ŸŽฅ: Follow video courses and tutorials.
    - Solve Challenges ๐Ÿงฉ: On platforms like LeetCode, HackerRank, and CodeWars.

15. Teach and Share Knowledge ๐Ÿ“ข
    - Write Blogs โœ๏ธ
    - Create Video Tutorials ๐Ÿ“น
    - Mentor Others ๐Ÿ‘จโ€๐Ÿซ

I have curated the best interview resources to crack Python Interviews ๐Ÿ‘‡๐Ÿ‘‡
https://topmate.io/coding/898340

Hope you'll like it

Like this post if you need more resources like this ๐Ÿ‘โค๏ธ
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๐Ÿ“ ๐–๐š๐ฒ๐ฌ ๐ญ๐จ ๐€๐ฉ๐ฉ๐ฅ๐ฒ ๐Ÿ๐จ๐ซ ๐ƒ๐š๐ญ๐š ๐€๐ง๐š๐ฅ๐ฒ๐ฌ๐ญ ๐‰๐จ๐›๐ฌ

๐Ÿ”ธ๐”๐ฌ๐ž ๐‰๐จ๐› ๐๐จ๐ซ๐ญ๐š๐ฅ๐ฌ
Job boards like LinkedIn & Naukari are great portals to find jobs.

Set up job alerts using keywords like โ€œData Analystโ€ so youโ€™ll get notified as soon as something new comes up.

๐Ÿ”ธ๐“๐š๐ข๐ฅ๐จ๐ซ ๐˜๐จ๐ฎ๐ซ ๐‘๐ž๐ฌ๐ฎ๐ฆ๐ž
Donโ€™t send the same resume to every job.

Take time to highlight the skills and tools that the job description asks for, like SQL, Power BI, or Excel. It helps your resume get noticed by software that scans for keywords (ATS).

๐Ÿ”ธ๐”๐ฌ๐ž ๐‹๐ข๐ง๐ค๐ž๐๐ˆ๐ง
Connect with recruiters and employees from your target companies. Ask for referrals when any jib opening is poster

Engage with data-related content and share your own work (like project insights or dashboards).

๐Ÿ”ธ๐‚๐ก๐ž๐œ๐ค ๐‚๐จ๐ฆ๐ฉ๐š๐ง๐ฒ ๐–๐ž๐›๐ฌ๐ข๐ญ๐ž๐ฌ ๐‘๐ž๐ ๐ฎ๐ฅ๐š๐ซ๐ฅ๐ฒ
Most big companies post jobs directly on their websites first.

Create a list of companies youโ€™re interested in and keep checking their careers page. Itโ€™s a good way to find openings early before they post on job portals.

๐Ÿ”ธ๐…๐จ๐ฅ๐ฅ๐จ๐ฐ ๐”๐ฉ ๐€๐Ÿ๐ญ๐ž๐ซ ๐€๐ฉ๐ฉ๐ฅ๐ฒ๐ข๐ง๐ 
After applying to a job, it helps to follow up with a quick message on LinkedIn. You can send a polite note to recruiter and aks for the update on your candidature.
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๐‹๐ข๐ฌ๐ญ ๐จ๐Ÿ ๐œ๐จ๐ฆ๐ฉ๐š๐ง๐ข๐ž๐ฌ ๐ญ๐ก๐š๐ญ ๐ก๐ข๐ซ๐ž ๐๐š๐ญ๐š ๐š๐ง๐š๐ฅ๐ฒ๐ฌ๐ญ๐ฌ:
TMcKinsey & Company
Boston Consulting Group (BCG)
Bain & Company
Deloitte
PwC
Ernst & Young (EY)
KPMG
Accenture
Google
Amazon
Microsoft
IBM
Oracle
Tiger Analytics
Mu Sigma
Fractal Analytics
EXL Service
ZS Associates
Wells Fargo
Walmart
Target
LTIMindtree
Infosys
TCS (Tata Consultancy Services)
Wipro
HCL Technologies
Capgemini
Cognizant

These companies often hire data analysts to use data for making decisions and planning strategically for their clients.
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Data Analyst Cheatsheet ๐Ÿ’ช
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How to Merge Pandas DataFrames?
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Data Analytics isn't rocket science. It's just a different language.

Here's a beginner's guide to the world of data analytics:

1) Understand the fundamentals:
- Mathematics
- Statistics
- Technology

2) Learn the tools:
- SQL
- Python
- Excel (yes, it's still relevant!)

3) Understand the data:
- What do you want to measure?
- How are you measuring it?
- What metrics are important to you?

4) Data Visualization:
- A picture is worth a thousand words

5) Practice:
- There's no better way to learn than to do it yourself.

Data Analytics is a valuable skill that can help you make better decisions, understand your audience better, and ultimately grow your business.

It's never too late to start learning!
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Essential Topics to Master Data Analytics Interviews: ๐Ÿš€

SQL:
1. Foundations
- SELECT statements with WHERE, ORDER BY, GROUP BY, HAVING
- Basic JOINS (INNER, LEFT, RIGHT, FULL)
- Navigate through simple databases and tables

2. Intermediate SQL
- Utilize Aggregate functions (COUNT, SUM, AVG, MAX, MIN)
- Embrace Subqueries and nested queries
- Master Common Table Expressions (WITH clause)
- Implement CASE statements for logical queries

3. Advanced SQL
- Explore Advanced JOIN techniques (self-join, non-equi join)
- Dive into Window functions (OVER, PARTITION BY, ROW_NUMBER, RANK, DENSE_RANK, lead, lag)
- Optimize queries with indexing
- Execute Data manipulation (INSERT, UPDATE, DELETE)

Python:
1. Python Basics
- Grasp Syntax, variables, and data types
- Command Control structures (if-else, for and while loops)
- Understand Basic data structures (lists, dictionaries, sets, tuples)
- Master Functions, lambda functions, and error handling (try-except)
- Explore Modules and packages

2. Pandas & Numpy
- Create and manipulate DataFrames and Series
- Perfect Indexing, selecting, and filtering data
- Handle missing data (fillna, dropna)
- Aggregate data with groupby, summarizing data
- Merge, join, and concatenate datasets

3. Data Visualization with Python
- Plot with Matplotlib (line plots, bar plots, histograms)
- Visualize with Seaborn (scatter plots, box plots, pair plots)
- Customize plots (sizes, labels, legends, color palettes)
- Introduction to interactive visualizations (e.g., Plotly)

Excel:
1. Excel Essentials
- Conduct Cell operations, basic formulas (SUMIFS, COUNTIFS, AVERAGEIFS, IF, AND, OR, NOT & Nested Functions etc.)
- Dive into charts and basic data visualization
- Sort and filter data, use Conditional formatting

2. Intermediate Excel
- Master Advanced formulas (V/XLOOKUP, INDEX-MATCH, nested IF)
- Leverage PivotTables and PivotCharts for summarizing data
- Utilize data validation tools
- Employ What-if analysis tools (Data Tables, Goal Seek)

3. Advanced Excel
- Harness Array formulas and advanced functions
- Dive into Data Model & Power Pivot
- Explore Advanced Filter, Slicers, and Timelines in Pivot Tables
- Create dynamic charts and interactive dashboards

Power BI:
1. Data Modeling in Power BI
- Import data from various sources
- Establish and manage relationships between datasets
- Grasp Data modeling basics (star schema, snowflake schema)

2. Data Transformation in Power BI
- Use Power Query for data cleaning and transformation
- Apply advanced data shaping techniques
- Create Calculated columns and measures using DAX

3. Data Visualization and Reporting in Power BI
- Craft interactive reports and dashboards
- Utilize Visualizations (bar, line, pie charts, maps)
- Publish and share reports, schedule data refreshes

Statistics Fundamentals:
- Mean, Median, Mode
- Standard Deviation, Variance
- Probability Distributions, Hypothesis Testing
- P-values, Confidence Intervals
- Correlation, Simple Linear Regression
- Normal Distribution, Binomial Distribution, Poisson Distribution.

Show some โค๏ธ if you're ready to elevate your data analytics journey! ๐Ÿ“Š

ENJOY LEARNING ๐Ÿ‘๐Ÿ‘
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SQL From Basic to Advanced level

Basic SQL is ONLY 7 commands:
- SELECT
- FROM
- WHERE (also use SQL comparison operators such as =, <=, >=, <> etc.)
- ORDER BY
- Aggregate functions such as SUM, AVERAGE, COUNT etc.
- GROUP BY
- CREATE, INSERT, DELETE, etc.
You can do all this in just one morning.

Once you know these, take the next step and learn commands like:
- LEFT JOIN
- INNER JOIN
- LIKE
- IN
- CASE WHEN
- HAVING (undertstand how it's different from GROUP BY)
- UNION ALL
This should take another day.

Once both basic and intermediate are done, start learning more advanced SQL concepts such as:
- Subqueries (when to use subqueries vs CTE?)
- CTEs (WITH AS)
- Stored Procedures
- Triggers
- Window functions (LEAD, LAG, PARTITION BY, RANK, DENSE RANK)
These can be done in a couple of days.
Learning these concepts is NOT hard at all

- what takes time is practice and knowing what command to use when. How do you master that?
- First, create a basic SQL project
- Then, work on an intermediate SQL project (search online) -

Lastly, create something advanced on SQL with many CTEs, subqueries, stored procedures and triggers etc.

This is ALL you need to become a badass in SQL, and trust me when I say this, it is not rocket science. It's just logic.

Remember that practice is the key here. It will be more clear and perfect with the continous practice

Best telegram channel to learn SQL: https://t.iss.one/sqlanalyst

Data Analyst Jobs๐Ÿ‘‡
https://t.iss.one/jobs_SQL

Join @free4unow_backup for more free resources.

Like this post if it helps ๐Ÿ˜„โค๏ธ

ENJOY LEARNING ๐Ÿ‘๐Ÿ‘
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Data analytics is not about the the tools you master but about the people you influence.

I see many debates around the best tools such as:

- Excel vs SQL
- Python vs R
- Tableau vs PowerBI
- ChatGPT vs no ChatGPT

The truth is that business doesn't care about how you come up with your insights.

All business cares about is:

- the story line
- how well they can understand it
- your communication style
- the overall feeling after a presentation

These make the difference in being perceived as a great data analyst...

not the tools you may or may not master ๐Ÿ˜…
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pandas Cheatsheet.pdf
11.1 MB
Pandas complete Cheatsheet ๐Ÿผ

React โค๏ธ for more
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Important questions to ace your machine learning interview with an approach to answer:

1. Machine Learning Project Lifecycle:
   - Define the problem
   - Gather and preprocess data
   - Choose a model and train it
   - Evaluate model performance
   - Tune and optimize the model
   - Deploy and maintain the model

2. Supervised vs Unsupervised Learning:
   - Supervised Learning: Uses labeled data for training (e.g., predicting house prices from features).
   - Unsupervised Learning: Uses unlabeled data to find patterns or groupings (e.g., clustering customer segments).

3. Evaluation Metrics for Regression:
   - Mean Absolute Error (MAE)
   - Mean Squared Error (MSE)
   - Root Mean Squared Error (RMSE)
   - R-squared (coefficient of determination)

4. Overfitting and Prevention:
   - Overfitting: Model learns the noise instead of the underlying pattern.
   - Prevention: Use simpler models, cross-validation, regularization.

5. Bias-Variance Tradeoff:
   - Balancing error due to bias (underfitting) and variance (overfitting) to find an optimal model complexity.

6. Cross-Validation:
   - Technique to assess model performance by splitting data into multiple subsets for training and validation.

7. Feature Selection Techniques:
   - Filter methods (e.g., correlation analysis)
   - Wrapper methods (e.g., recursive feature elimination)
   - Embedded methods (e.g., Lasso regularization)

8. Assumptions of Linear Regression:
   - Linearity
   - Independence of errors
   - Homoscedasticity (constant variance)
   - No multicollinearity

9. Regularization in Linear Models:
   - Adds a penalty term to the loss function to prevent overfitting by shrinking coefficients.

10. Classification vs Regression:
    - Classification: Predicts a categorical outcome (e.g., class labels).
    - Regression: Predicts a continuous numerical outcome (e.g., house price).

11. Dimensionality Reduction Algorithms:
    - Principal Component Analysis (PCA)
    - t-Distributed Stochastic Neighbor Embedding (t-SNE)

12. Decision Tree:
    - Tree-like model where internal nodes represent features, branches represent decisions, and leaf nodes represent outcomes.

13. Ensemble Methods:
    - Combine predictions from multiple models to improve accuracy (e.g., Random Forest, Gradient Boosting).

14. Handling Missing or Corrupted Data:
    - Imputation (e.g., mean substitution)
    - Removing rows or columns with missing data
    - Using algorithms robust to missing values

15. Kernels in Support Vector Machines (SVM):
    - Linear kernel
    - Polynomial kernel
    - Radial Basis Function (RBF) kernel

Data Science Interview Resources
๐Ÿ‘‡๐Ÿ‘‡
https://topmate.io/coding/914624

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A-Z of essential data science concepts

A: Algorithm - A set of rules or instructions for solving a problem or completing a task.
B: Big Data - Large and complex datasets that traditional data processing applications are unable to handle efficiently.
C: Classification - A type of machine learning task that involves assigning labels to instances based on their characteristics.
D: Data Mining - The process of discovering patterns and extracting useful information from large datasets.
E: Ensemble Learning - A machine learning technique that combines multiple models to improve predictive performance.
F: Feature Engineering - The process of selecting, extracting, and transforming features from raw data to improve model performance.
G: Gradient Descent - An optimization algorithm used to minimize the error of a model by adjusting its parameters iteratively.
H: Hypothesis Testing - A statistical method used to make inferences about a population based on sample data.
I: Imputation - The process of replacing missing values in a dataset with estimated values.
J: Joint Probability - The probability of the intersection of two or more events occurring simultaneously.
K: K-Means Clustering - A popular unsupervised machine learning algorithm used for clustering data points into groups.
L: Logistic Regression - A statistical model used for binary classification tasks.
M: Machine Learning - A subset of artificial intelligence that enables systems to learn from data and improve performance over time.
N: Neural Network - A computer system inspired by the structure of the human brain, used for various machine learning tasks.
O: Outlier Detection - The process of identifying observations in a dataset that significantly deviate from the rest of the data points.
P: Precision and Recall - Evaluation metrics used to assess the performance of classification models.
Q: Quantitative Analysis - The process of using mathematical and statistical methods to analyze and interpret data.
R: Regression Analysis - A statistical technique used to model the relationship between a dependent variable and one or more independent variables.
S: Support Vector Machine - A supervised machine learning algorithm used for classification and regression tasks.
T: Time Series Analysis - The study of data collected over time to detect patterns, trends, and seasonal variations.
U: Unsupervised Learning - Machine learning techniques used to identify patterns and relationships in data without labeled outcomes.
V: Validation - The process of assessing the performance and generalization of a machine learning model using independent datasets.
W: Weka - A popular open-source software tool used for data mining and machine learning tasks.
X: XGBoost - An optimized implementation of gradient boosting that is widely used for classification and regression tasks.
Y: Yarn - A resource manager used in Apache Hadoop for managing resources across distributed clusters.
Z: Zero-Inflated Model - A statistical model used to analyze data with excess zeros, commonly found in count data.

Data Science Interview Resources
๐Ÿ‘‡๐Ÿ‘‡
https://whatsapp.com/channel/0029Va4QUHa6rsQjhITHK82y

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Best free resources to learn AI ๐Ÿ˜ป๐Ÿ™Œ
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