1
Google Sheets: advanced formulas (VLOOKUP, INDEX/MATCH, ARRAYFORMULA), pivot tables, automation
2
SQL: SELECT, JOIN, GROUP BY, HAVING, window functions (ROW_NUMBER, RANK, LAG/LEAD), CTEs, subqueries
3
BigQuery: partitioning, clustering, nested queries, cost optimization, UDFs
4
Data Modeling: star schemas, fact and dimension tables, normalization, denormalization
5
KPIs & Metrics: CAC, LTV, MRR, ARR, churn rate, NPS, conversion rate, ARPU
6
Funnels & Cohorts: conversion analysis, cohort retention, RFM analysis
7
ELT & Data Pipeline: Extract-Load-Transform, dbt (models, tests, sources), orchestration
8
Zapier & automation: triggers, actions, multi-step workflows, webhooks
9
Google Tag Manager: tags, triggers, variables, dataLayer, tracking plans
10
Power BI: DAX, calculated measures, relationships, visualizations, filters, drill-down
11
Looker Studio: data sources, calculated fields, filters, parameters, blending
12
Visualization: choosing the right chart, data storytelling, design principles (Tufte)
13
AB Testing: hypotheses, sample size, statistical significance, p-value, Student's t-test
14
Python & Pandas: DataFrames, Series, groupby, merge, pivot_table, cleaning
15
Plotly: interactive charts, subplots, animations, dashboards
16
Scikit-Learn: regression, classification, clustering (K-Means), train/test split, metrics
17
Methodology: problem framing, source identification, cleaning, analysis, recommendations