DATA
Data Analyst Portfolio

Kolawole
Emmanuel
Oluwaseyi

Transforming raw data into powerful business insights. Skilled in Excel, Power BI, SQL & Python — building dashboards, writing complex queries and developing ML models that drive smarter decisions.

13
Projects
Excel
Advanced
Power BI
DAX & Reports
SQLSQL
Queries & EDA
PyPython
ML & Analysis
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Tools & Expertise

My Skill Set

Built through 13 real-world projects spanning business analytics, data science and machine learning.

Microsoft Excel
Pivot Tables · Power Query · Advanced Formulas · Maps · Charts
Microsoft Power BI
DAX · Interactive Dashboards · Data Modelling · Multi-page Reports
SQL
SQL
Joins · CTEs · Window Functions · LAG · RANK · Data Cleaning
Python
Python
pandas · scikit-learn · matplotlib · Jupyter · Machine Learning
Data Analysis
KPIs · Trend Analysis · Statistical Correlation · Business Storytelling
Data Visualization
Charts · Maps · Executive Dashboards · ML Plots · Reports

Featured Work

My Projects

13 real projects solving real problems — click a tool below to filter by category.

Executive Sales Dashboard
Excel
01
ExcelPivot TablesPower QueryDashboard
Executive Sales Dashboard
⚡ Business had $1.6M in sales data spread across stores, regions and salespersons with no single view to track performance, identify top performers or spot underperforming areas.

Built a fully dynamic Excel executive dashboard with KPI cards, bubble charts, sparklines and interactive slicers — giving leadership a real-time view of sales performance across every dimension.

Total revenue of $1.6M — up 29% vs prior year with 271 total orders processed
Tablets led all products at $289.9K contributing 17.89% of total revenue
Ryan was top regional manager at $368.5K · North region outperformed all 5 regions
Retail segment accounted for 52.27% of sales · Cash was the #1 payment method at $374.7K
Women Involvement & Peacebuilding — Plateau State, Nigeria
Excel
02
ExcelPivot TablesSurvey AnalysisDashboard
Women Involvement & Peacebuilding — Plateau State, Nigeria
⚡ Local government needed data to understand women's actual participation in peacebuilding, what barriers they face and what strategies would work — based on 400 real survey responses across 6 LGAs.

Analyzed a 400-respondent survey across Bassa, Jos North, Jos South, Wase, Mangu and Shendem LGAs. Used Excel Pivot Tables and dashboard design to surface meaningful patterns in gender, participation and policy needs.

282 of 400 respondents (70.5%) were female — showing strong female representation
184 respondents confirmed women play an active and significant role in peacebuilding efforts
Lack of resources & funding was the #1 barrier cited by 160 respondents — 40% of all responses
Legal reforms to protect women in politics was the top recommended strategy at 140 responses
Customer Feedback Sentiment Analysis
Power BI
03
Power BIDAXSentiment AnalysisDashboard
Customer Feedback Sentiment Analysis
⚡ Company had 40,000 feedback entries across 10 products and 100 customers but no structured way to track customer satisfaction, which products had problems or how sentiment changed month by month.

Built an interactive Power BI dashboard with dynamic slicers for product and feedback type — allowing management to drill into sentiment patterns, compare products and monitor monthly feedback volumes in real time.

60.12% of all 40,000 feedback entries were positive — indicating overall customer satisfaction
Product G and Product A led all products with 4.1K feedback entries each throughout the year
May recorded the highest monthly feedback at 3,533 entries · February was the lowest at 3,093
Suggestions (13,386), Complaints (13,366) and Praise (13,248) were almost perfectly evenly distributed
Healthcare Analysis Dashboard & Insights
Power BI
04
Power BIDAXHealthcare Analytics3-Page Report
Healthcare Analysis Dashboard & Insights
⚡ Hospital network had no unified view of 55,500 patient records — administrators could not track common conditions, billing variations across insurance providers or how admission types affected costs.

Built a 3-page Power BI report (Overview, Medical Insights, Billing Dashboard) giving hospital leadership full visibility into patient demographics, disease patterns, insurance billing and yearly financial trends from 2019–2024.

Total billing reached $1.42bn across 55,500 patients in 40K hospitals over 6 years
Middle-aged adults were the largest patient group at 20.5K · Elderly at 9K · Old-Aged at 8.1K
Germany had significantly higher discharge rates vs Spain (16.67%) and France (16.17%)
Urgent admissions generated the highest billing at $479.49M · 2021 was the peak billing year at $286.55M
Personal Finance Tracker
Excel
05
ExcelDashboardFinancial ModellingCalculations
Personal Finance Tracker
⚡ Individual earning from 3 different income sources had no clear dashboard to track available balance, monitor expense categories or understand weekly and monthly spending patterns.

Built a dynamic personal finance dashboard in Excel with a credit card balance view, income source breakdown, expense category ranking and both monthly and weekly trend charts — all with interactive month slicers.

Available balance of $35,249 from total income of $65,440 against total expenses of $30,191
Data with Decisions platform contributes 76% of all income at $50,000 — the dominant source
Housing is the biggest expense at $9,000 followed by Groceries at $6,454 and Clothes at $4,304
Monday recorded the highest weekly spending · Max single expense was $900 · Max income $1,500
Nigeria Car Market Dashboard
Excel
06
ExcelMap VisualizationMarket AnalysisDashboard
Nigeria Car Market Dashboard
⚡ No structured data analysis existed of the Nigerian car market — buyers, sellers and analysts had no visibility into pricing, popular brands, transmission preferences or regional hotspots across Nigeria.

Analyzed the Nigerian car market using data from Car45.com. Built an Excel dashboard with integrated Bing map visualization covering vehicle metrics, top models, colour preferences and geographic sales distribution.

Average car price in Nigeria is ₦5.0M with avg mileage 28.4K km, 217hp and 3.1K cc engine
Toyota leads the Nigerian car market significantly over Volkswagen, Nissan and Mercedes-Benz
94% of Nigerian drivers prefer Automatic transmission — only 6% opt for Manual gearbox
Lagos and Abuja are the primary car sales hotspots accounting for the majority of market volume
Business Performance & Customer Insights
Excel
07
ExcelKPI DashboardMap VisualizationCustomer Analysis
Business Performance & Customer Insights
⚡ Business was tracking sales, profit and customer satisfaction in scattered spreadsheets with no unified view of performance vs target, regional breakdown, customer growth or experience quality scores.

Built a professional Excel KPI dashboard with quarterly filters, monthly sales vs target trend lines, regional donut chart, customer growth bar chart, customer experience ratings and a live geographical map.

Sales of $157,361 at 86% completion rate vs $166,999 target — 14% gap flagged for action
Profit of $113,301 at 85% CR · Customer acquisition at 84% with 63 total customers onboarded
East region leads all regions in sales distribution at 32% · followed by North, South and West
Speed is the highest-rated customer experience factor at 96 · Availability is the weakest at only 41
Bank Customer Churn Analysis Dashboard
Excel
08
ExcelChurn AnalysisStatistical AnalysisMap Visualization
Bank Customer Churn Analysis Dashboard
⚡ Bank was losing 20% of customers with no data-driven understanding of who was churning, why they were leaving, which demographics were highest risk or what the financial profile of churned customers looked like.

Built a multi-page Excel dashboard (Dashboard, Demographics, Analysis, Dataset) with scatter plots, correlation analysis, geographic churn map and a full written insights panel — a complete churn risk picture.

2,038 customers churned (20.38%) out of 10,000 total · 7,962 retained · Avg satisfaction 3.01/5
Germany had highest churn at 32.44% — significantly above Spain (16.67%) and France (16.17%)
Old age group churns most at 49.76% · Age-churn correlation confirmed at 0.50 — strongest predictor
Female churn (25.07%) significantly higher than male (16.47%) · Churned avg balance $91,109 vs $72,743
Pizza Sales Analysis — Excel & SQL
Excel + SQL
09
ExcelSQL ServerPivot TablesDashboard
Pizza Sales Analysis — Excel & SQL
⚡ Pizza restaurant had 21,350 orders but no structured analysis of which products drove revenue, when customers ordered most, which pizza sizes sold best or which items were consistently underperforming.

Wrote SQL queries in SQL Server to extract all KPIs, daily/hourly trends, category breakdowns and best/worst sellers. Then built a complete Excel dashboard visualizing all results with charts, slicers and business narrative.

Total revenue $817,860 · 21,350 orders · 49,574 pizzas sold · Avg order value $38.31
Friday is the busiest day at 3,538 orders · Peak hours are 12–1pm and 4–8pm every day
Classic category leads at 26.91% revenue share · Large size dominates at 45.89% of all orders
Classic Deluxe Pizza is the #1 best seller at 2,453 units · Brie Carre Pizza worst at only 490
World Layoffs — SQL Data Cleaning
SQL
10
SQL ServerData CleaningCTEsWindow Functions
World Layoffs — SQL Data Cleaning
⚡ A raw dataset of global tech company layoffs contained duplicates, inconsistent formatting, NULL values stored as strings, mismatched country names and wrong data types — making it completely unreliable for analysis.

Performed a full professional SQL data cleaning pipeline — working on a staging table to protect raw data, removing duplicates using CTEs, standardizing text values, handling NULLs and correcting data types throughout.

Created staging table using CREATE TABLE + INSERT SELECT to safely clean without touching raw data
Removed all duplicates using ROW_NUMBER() OVER(PARTITION BY 9 columns) inside a CTE — deleted row_num > 1
Standardized Crypto variants → "Crypto", trimmed company names, fixed "United States." trailing period
Converted total_laid_off to INT and funds_raised_millions to DECIMAL(10,2) after clearing NULL strings
World Layoffs — Exploratory Data Analysis (SQL)
SQL
11
SQL ServerEDACTEsLAG & RANK Functions
World Layoffs — Exploratory Data Analysis (SQL)
⚡ After cleaning the World Layoffs dataset, the business needed deep exploratory analysis to understand which companies, industries and countries were most affected and how the trend evolved month by month.

Conducted advanced SQL EDA using CTEs, window functions, rolling totals and LAG comparisons — uncovering layoff patterns by company, industry, country, year and funding stage across the entire cleaned dataset.

Built rolling monthly layoff totals using CTE + SUM() OVER(ORDER BY yr, mth ROWS UNBOUNDED PRECEDING)
Used DENSE_RANK() OVER(PARTITION BY yr) to find top 5 companies by layoffs for each year
LAG() function calculated month-over-month differences and tracked acceleration of layoffs over time
Companies with percentage_laid_off = 1 sorted by funds_raised_millions revealed the biggest collapses
Molecular Solubility Prediction — Machine Learning
Python
12
PythonJupyter Notebookscikit-learnLinear Regression
Molecular Solubility Prediction — Machine Learning
⚡ Predicting how well a drug compound dissolves in water traditionally requires expensive lab experiments. The goal was to build an ML model that predicts solubility computationally from molecular descriptors.

Built a Linear Regression ML model using the Delaney solubility dataset. Used MolWt, MolLogP, NumRotatableBonds and AromaticProportion as features to predict logS (aqueous solubility) with scikit-learn.

Features: MolWt, MolLogP, NumRotatableBonds, AromaticProportion — all key molecular descriptors
Applied train_test_split (80/20) then trained LinearRegression model from scikit-learn on training set
Achieved R² score of 0.7374 — model explains 73.74% of variance in molecular solubility
Directly applies a First-Class BSc Chemistry background to real machine learning drug prediction
Wine Chemical Composition Classification — ML
Python
13
PythonJupyter Notebookscikit-learnpandas · matplotlib
Wine Chemical Composition Classification — ML
⚡ Wine quality classification is typically done by expert sommeliers — a slow subjective process. The goal was to build an ML model that classifies wine samples objectively from chemical composition data.

Loaded the sklearn wine dataset (178 samples, 14 chemical features). Performed EDA then built a classification model — demonstrating how chemistry domain knowledge drives better feature interpretation.

Dataset: 178 wine samples · 14 features including alcohol, malic_acid, ash, flavanoids, magnesium
Used sklearn load_wine() · df.head() showed clear chemical variation across wine classification groups
Applied full ML pipeline: data loading → EDA → feature selection → model training → evaluation
Chemistry domain knowledge drives better ML feature interpretation — a rare cross-disciplinary skill

About Me

// Who I Am

Turning Data Into
Decisions That Matter

I'm Kolawole Emmanuel Oluwaseyi, a Data Analyst with a First-Class BSc in Chemistry from the University of Ibadan. I work across Excel, Power BI, SQL and Python — with 13 projects spanning healthcare, banking, finance, market analysis, social research and machine learning.

My Chemistry background is not just academic — I have applied it directly in ML projects predicting molecular solubility and classifying wine compounds, making me a uniquely cross-disciplinary analyst that bridges science and data.

I focus on the business question first, then craft the right analysis to answer it clearly and visually — building solutions that people actually use and trust.

See My Work → Hire Me
kolawole.json
{
  "name": "Kolawole Emmanuel Oluwaseyi",
  "role": "Data Analyst",
  "education": "BSc Chemistry (First Class)",
  "tools": ["Excel","Power BI","SQL","Python"],
  "projects": 13,
  "domains": ["Healthcare", "Banking",
    "Finance", "Market Analysis", "ML"],
  "twitter": "@Kollzemmy123",
  "available": true
}

Open to Opportunities

Looking to hire a data analyst or collaborate on a project? Fill in the form and I will get back to you. Currently open to full-time, freelance and internship opportunities.

✉
Email
kolawoleemmanuel2012@gmail.com
𝕏
Twitter / X
@Kollzemmy123
💼
LinkedIn
Emmanuel Kolawole
🐱
GitHub
github.com/Kollzemmist

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