# Mission: Data/Business Analyst interview prep

## Why
Clear a Data/Business Analyst interview happening within a week (as of 2026-10-14). The rounds are expected to cover an aptitude test, a group discussion, and technical questions on Excel, SQL and statistics. The goal is to answer the commonly asked questions out loud with confidence and solve the practical tasks on the spot.

## Success looks like
- Write VLOOKUP / XLOOKUP / HLOOKUP and INDEX+MATCH from memory, and explain when to use each one
- Build a Pivot Table and use core formulas (SUMIFS, COUNTIFS, IF, IFERROR) on a sample dataset
- Write SQL using JOINs (especially LEFT JOIN, and how it compares to VLOOKUP), GROUP BY / HAVING and ORDER BY, and state the logical order of execution
- Define mean, median and mode, Type I and Type II errors, p-values and hypothesis tests, and multicollinearity, each with a business example
- Solve water-jug style puzzles, AP, speed/time/distance (trains) and coding-decoding questions under time pressure
- Make 3–4 structured points in a GD on "AI's impact on IT companies"

## Constraints
- Under 1 week: favour the most-asked questions over exhaustive coverage
- Beginner across most topics
- Learns visually first, plus doing and reading

## Out of scope
- Advanced Excel (VBA, Power Query, DAX), window functions beyond a mention, regression maths derivations