Crazycoder Blog — Data Analyst Guides

• P-values and A/B Testing Explained (Without the Jargon) — A clear, honest explanation of p-values, statistical significance and A/B testing for data analysts — what they really mean, the mistakes everyone makes, and how to read a test result correctly.
• VLOOKUP vs XLOOKUP: Which to Use, and Why XLOOKUP Usually Wins — A plain-English comparison of Excel's VLOOKUP and XLOOKUP — how each works, where VLOOKUP breaks, and why XLOOKUP is the better default, with guidance for beginners and power users.
• Pandas groupby Explained: From Basics to Real Analyst Workflows — A clear, level-by-level guide to pandas groupby — the single most useful pandas skill for analysts. Covers aggregation, transform, multiple keys, named aggregations and real patterns like cohorts and RFM.
• 20 SQL Interview Questions Analysts Get Asked (With How to Think About Them) — The SQL question types that actually come up in data-analyst interviews at top companies — from basic filtering to window functions and gaps-and-islands — with how to approach each, for beginners through advanced.
• How to Become a Data Analyst in 2026: A Step-by-Step Roadmap — A practical, no-fluff roadmap to becoming a data analyst — the exact skills to learn in order (Excel, SQL, Python, Power BI, Statistics), how long each takes, and how to prove them to employers.