Python
A/B Testing for Data Analysts: From Hypothesis to Decision
Complete A/B testing workflow: hypothesis formulation, sample size calculation, z-test in Python, p-value interpretation and common pitfalls to avoid.
SQL
SQL Window Functions: Complete Guide for Data Analysts
ROW_NUMBER, RANK, LAG, LEAD, running totals and moving averages — every window function an analyst needs with real use cases and ready code.
Visualization
Tableau vs Power BI vs Looker Studio: Which BI Tool to Use in 2026
Pricing, features and learning curve compared — practical guide to choosing the right BI tool for your workflow in 2026.
Python
Cohort Analysis & Retention in Python
Build a retention matrix, heatmap and churn calculation from raw transaction data — complete guide with pandas code.
SQL
dbt for Data Analysts in 2026
Modern SQL transformation with dbt Core: models, tests, documentation and lineage — no engineering background needed.
AI Tools
AI-Assisted Data Analysis in 2026
How to use ChatGPT, GitHub Copilot and PandasAI to work 3× faster — with real prompts and code examples.