Олександр

Oleksandr Romanyshyn
Data analyst, Product analyst
Ternopil, Ukraine

Summary
Junior Data analyst with hands-on experience in Python, Pandas,
and SQL for data analysis and manipulation. Solid understanding of
Contact me statistics and data exploration techniques to uncover trends and
[открыть контакты](см. выше в блоке «контактная информация») (Mobile) support decision-making.
[открыть контакты](см. выше в блоке «контактная информация»)(email) Proficient in using Tableau for creating clear, interactive
LinkedIn visualizations. Easier to apply analytical skills in real-world projects.

GitHub Experience
Kaggle
[10-01-2026 - Present] Junior data analyst – Remote Helpers
Languages Cohort analysis of user retention and optimization of marketing
• English(B2) strategy
• Ukrainian(Native) Technical implementation:

Data processing: Implemented raw transaction data cleaning in
Hard skills Python/Pandas, duplicate processing, and type conversion. Used the
• Excel
pandas method’s to segment users by date of first purchase.
• SQL Complex calculations: Optimized the calculation of customer
• Python(Numpy, Pandas, Scipy) lifetime through Pandas vector operations, which accelerated data
processing by 5 times compared to loops.
• Business metrics
• Statistics Visualization: Built a retention matrix and visualized it as a heat
map with color coding for quick detection of anomalies in cohort
• BI (Tableau, PowerBI)
behavior.

Analytical implementation:
Soft skills
• Sociability Conducted a cohort analysis, revealing a twofold difference in
retention rates between the January (36%) and July (18%) cohorts.
• Adaptability
Identified a downward trend in the retention of older customers, which
• Stress-resistant allowed us to formulate hypotheses about low traffic quality and
• Quick learner seasonal shortages of goods.
• Critical thinking
Education
Courses Ternopil Ivan Puluj National Technical University
Bachelor of Science, Computer Engineering · [September 2021 - June 2025]
• SQL – SQLAcademy
• Data cleaning – Kaggle
• Data visualization – Kaggle
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• Excel – W3Schools