A/B Testing for Data Analysts
From hypothesis to decision: sample size, z-test in Python, p-value interpretation and the mistakes that invalidate tests.
Isachenko Andrii
I'm Data Analyst
About
Andrii Isachenko
Data Analyst | Open to work
Summary
Data Analyst with experience in analyzing complex datasets and transforming data into actionable insights. Proficient in Excel, Google Sheets, SQL, and basic Python (Pandas, NumPy), with hands-on experience in data visualization using Looker, Tableau, and Power BI. Motivated to grow in data analytics and support data-driven decision-making.
- Location: Ukraine
- Work format: Remote
- Employment: Freelance, Part-time
- Resume: My resume (ATS)
Skills
Skills of working with data at all stages: collection, cleaning, analysis, visualization and automation of reporting using SQL, Python and BI tools.
Excel / Sheets 90%
SQL 85%
Python 75%
AI Tools 90%
PowerPoint / Presentations 90%
Looker Studio 80%
Tableau Public 90%
Power BI 85%
Resume
A data analyst who combines management experience and technical skills to make decisions based on data
Specialized Education
IT SCHOOL "GOIT"
2025 - 2026
Data Analysis
- Data analysis basics (ETL, EDA, Sheets, SQL, BigQuery)
- Python (Pandas, NumPy, SeaBorn, Matplotlib) + A/B testing
- Data visualization and BI tools (Looker, Tableau, Power BI)
- AI for Data Analytics (Gemini, ChatGPT, Copilot, Pandas AI)
Education
NAU "KHAI"
2006 - 2007, Specialist
Organizational Management
Integration of management skills with sales analytics and forecasting
KEIM (ECOMEN)
2002 - 2006, Bachelor
Management
Management of business processes and the team based on data analysis
Work Experience
Senior sales consultant
2024 - 2025
"EPICENTR K" LLC
- Analysis of sales and KPI
- Assortment and inventory management
- Client analytics
- Forecasting and planning
- Team effectiveness
Achievements: career growth - from an intern to a senior salesperson in less than a year, which confirms the ability to quickly adapt, learn and deliver results
Engineer of ASKOE
2024
"POLTAVAOBLENERGO" JSC
- Commercial electricity metering.
- Setup and maintenance of accounting systems
- Control and reporting
Portfolio
Practical projects on data analysis, construction of KPI-dashboards and automation of reporting in SQL and Python.
- All
- Sheets
- SQL
- Python
- Visualization
Services
Need help with data processing and analysis, dashboard building, and automated reporting to support business decisions? Contact me!
Data Acquisition
Configuring data flows from internal databases (SQL), external services via APIs and websites. Creating a single repository of information from all available sources.
Data Cleaning
Quality check, removal of duplicates and correction of errors in data sets. Bringing disparate information into a single format suitable for correct analysis.
Data Analysis
Calculating key performance indicators (KPIs), finding hidden patterns, and testing business hypotheses. Transforming numbers into concrete conclusions about the causes of business changes.
Data Visualization
Development of interactive dashboards and graphs that clearly reflect the state of affairs. Creation of tools for quick visual monitoring of processes in real time.
Reporting
Preparation of regular analytical reports and presentations with clear recommendations for management. Adaptation of complex technical conclusions to the requests of the business customer.
Automation
Creating scripts and systems for automatic report updates without human intervention. Setting up instant notifications about critical changes in indicators.
Articles
Thoughts on data analytics, SQL, Python and BI tools — practical insights from real projects.
Python
2026-06-12
SQL
2026-05-05
SQL Window Functions: Complete Guide
ROW_NUMBER, RANK, LAG, running totals and moving averages — every window function an analyst needs with real use cases.
Visualization
2026-04-10
Tableau vs Power BI vs Looker Studio 2026
Pricing, features and learning curve compared — practical guide to choosing the right BI tool for your workflow.
Contact
I am open to work. Feel free to get in touch with me.
