Imonikhe Ayeni | Learning LibraryBack to portfolio
Practical data learning

Build practical data skills, one guide at a time.

Learn the concepts, practise the tools, refresh what you have forgotten and prepare for technical interviews across modern data and analytics work.

Search by tool, topic or interview term.

Browse core guidesChoose a learning path
LearnUnderstand the concept in plain language before worrying about syntax.
PractiseWork through examples, change the inputs and check the output yourself.
RefreshReturn to searchable definitions and examples when a topic comes up at work.
PrepareUse technical, practical and behavioural interview material before applications and interviews.
Choose a route

Start with the path closest to your goal.

You do not need to complete the library in numerical order. The part numbers organise the collection; the paths below show useful combinations.

Data Analyst & BI

Reporting and dashboard route

For spreadsheet analysis, querying, dashboards and reusable business metrics.

Excel → SQL → Power BI → DAX
Data Science

Programming and modelling route

For coding, data preparation, statistical work and machine-learning foundations.

Python → SQL → R
Research & Statistics

Analysis and reproducibility route

For structured data analysis, statistical testing and clear reporting.

R → Excel → SQL
All guides

Core learning guides

Choose a subject and work from fundamentals toward practical analysis. Each guide also includes a refresher and interview section.

Start simple

Begin with the foundations. Advanced material stays further down each guide.

Practise, don’t memorise

Retype examples, change values and check the result yourself.

Use it as a reference

Search for a forgotten concept and return to the full guide when you need more context.

Interview ready

Revise terminology, practical tasks and behavioural questions before interviews.