Marek Wisniewski

Data Scientist | Python | SQL | Machine Learning | Excel

marekwisniewskiuk@gmail.com | GitHub

About Me

I am a motivated and detail-oriented Data Scientist with a background in physics and natural sciences. I transitioned into data science to combine my analytical thinking with technology to solve real-world problems. I enjoy uncovering insights from data, building predictive models, and continuously learning new tools and techniques.

Skills

Education

Work Smarter with Microsoft Excel (via Coursera)

09/2025 to 09/2025

Completed a certified course in Microsoft Excel, developing strong skills in creating and managing spreadsheets, using formulas and functions, organising and visualising data, and improving productivity with Microsoft 365 tools.

Data Science – IBM (via Coursera)

07/2024 to 03/2025

Successfully completed a professional certification program in data science, gaining skills in data analysis, visualization, machine learning, and working with tools such as Python, SQL, and data analysis libraries.

AI Developer – IBM (via Coursera)

02/2024 to 06/2024

Successfully completed a professional certification program in AI development, gaining hands-on experience in machine learning, neural networks, and AI model deployment.

Python Intermediate – SoloLearn

03/2024 to 06/2024

Successfully completed a course covering the Python programming, including variables, data structures, loops, functions, and control flow. Gained foundational skills in writing clean and efficient Python code.

First Year of Natural Sciences – Open University, Manchester

03/2020 to 06/2021

Completed the first year of a Natural Sciences program, focusing on interdisciplinary studies in technology, mathematics, and science.

Physics (Discontinued) – University of Rzeszow, Poland

09/2002 to 03/2005

Studied physics at the undergraduate level before discontinuing to move to England. Gained a strong foundation in theoretical and applied physics.

Sales Analysis Report (Excel Project)

This project analyzes company sales performance across multiple countries, products, and customer segments using Microsoft Excel. The goal was to clean, analyze, and visualize sales data to identify revenue trends, profit margins, and top-performing products while comparing actual performance against predefined targets.
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Credit Risk Prediction (ML Project)

In this project, I built a machine learning model to predict whether a customer is likely to default on a loan using the German Credit dataset (UCI repository). I applied data preprocessing techniques such as one-hot encoding and scaling, then trained a balanced Random Forest classifier. The model achieved an accuracy of ~73% and an AUC score of ~0.79. I also analyzed feature importance and visualized the ROC curve to evaluate the model's performance. Tools used: Python, pandas, scikit-learn, seaborn, matplotlib

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Visualising User Sentiment in Spotify Reviews

Analysed user review text data from Spotify by cleaning the text, separating positive and negative sentiment, and identifying the most frequent words. Utilised Python (Pandas, NLTK, WordCloud) for sentiment analysis and created custom visualisations using a Spotify logo mask.

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