Career studio / Data Analytics
Build evidence for the Data Analyst role
A fictional training store needs to know which course format has the highest net sales. The source contains refunds and inconsistent labels. Build an analysis whose definitions can be reproduced.
Your outcome: Clean dataset, SQL analysis and a decision-focused report.
Start with the right expectations
Who this is for
Basic arithmetic and spreadsheet familiarity; SQL can be learned during the path.
This path develops a demonstrable work sample for the named role. It does not replace employer-specific experience, professional qualifications or supervised practice.
Plan your study time
Use a flexible six-week project schedule: one week for each of the first four stages and two weeks for the portfolio and review. Allow roughly 3–5 hours per week for the case work, in addition to course study. This is a planning suggestion, not a measured course duration or a promise of job readiness.
Read the course access notes before starting. Free viewing or reading does not automatically include certificates, graded assessments, software licences or paid cloud resources. Core case work can be documented with a free editor and spreadsheet; optional implementation tools may have additional requirements.
Your course sequence
Start in the order below. Use the course outline to select the sections relevant to the stage tasks, and complete foundation exercises before moving on. Full provider courses can be substantially longer than this project schedule. These are course resources, not a claimed count of individual lessons.
Resource 01 / Google
Free Data Analytics Course: Spreadsheets, SQL and R
Purpose: Build the foundations. Connect your notes to the case tasks below rather than only collecting completion marks.
Access: Free Video
Certificate: Free video viewing; a Google certificate is not included
Resource 02 / Harvard
CS 50’s Introduction to Databases with SQL
Purpose: Develop the role-specific method. Connect your notes to the case tasks below rather than only collecting completion marks.
- Query relational tables and connect records using primary and foreign keys.
- Model entities and relationships, choosing appropriate data types and constraints.
- Create, update and delete information while maintaining a clear database structure.
Access: Free CS 50 OpenCourseWare material and free development tools; free edX and GitHub accounts for assignment submission and free-certificate workflow. No required paid hosting or software.
Certificate: Free CS 50 certificate after at least 70% on every required problem and the final project; no automatic academic credit.
Resource 03 / Learn Skills Daily
Excel Data Analysis: Free Course
Purpose: Strengthen practical application. Connect your notes to the case tasks below rather than only collecting completion marks.
- Frame a small analytical question and identify the spreadsheet data needed to answer it.
- Use the course’s table, calculation and summary demonstrations to organise an analytical workbook.
- Follow the PivotTables training to investigate groups of records and review a summary.
Access: Free Video
Certificate: Free video viewing; certificate not included
Learn, make, check
Keep a decision log as you work. For each stage, capture the assumption, your work product, a check and the change you made after that check. The acceptance criterion is the stopping condition for the stage.
Stage 1 / suggested project week 1
Ask an answerable question
Understand: A business question needs a measure and scope.
Make: Define net sales, reporting period and format categories before opening a chart.
Check before moving on: Explain how refunds and missing values will be treated.
Study companion: Free Data Analytics Course: Spreadsheets, SQL and R. Use its relevant lessons and examples; the independent WikiFree task is not a provider assessment.
Save as evidence: a dated work product and a short note explaining one choice, one alternative and one remaining uncertainty.
Stage 2 / suggested project week 2
Clean with a record
Understand: Cleaning decisions should be reversible and auditable.
Make: Preserve raw data and create a change log for labels, duplicates and invalid values.
Check before moving on: Never silently discard inconvenient rows.
Study companion: CS 50’s Introduction to Databases with SQL. Use its relevant lessons and examples; the independent WikiFree task is not a provider assessment.
Save as evidence: a dated work product and a short note explaining one choice, one alternative and one remaining uncertainty.
Stage 3 / suggested project week 3
Analyze and reconcile
Understand: A grouped result should tie back to source totals.
Make: Compute gross sales, refunds and net sales by format in SQL or a spreadsheet.
Check before moving on: Check totals using an independent calculation.
Study companion: Excel Data Analysis: Free Course. Use its relevant lessons and examples; the independent WikiFree task is not a provider assessment.
Save as evidence: a dated work product and a short note explaining one choice, one alternative and one remaining uncertainty.
Stage 4 / suggested project week 4
Communicate uncertainty
Understand: A chart is evidence for a decision, not a substitute for context.
Make: Write a one-page recommendation with one chart and two limitations.
Check before moving on: Do not imply profitability when only revenue data are available.
Study companion: Excel Data Analysis: Free Course. Use its relevant lessons and examples; the independent WikiFree task is not a provider assessment.
Save as evidence: a dated work product and a short note explaining one choice, one alternative and one remaining uncertainty.
Stage 5 / suggested project weeks 5–6
Present your portfolio
Assemble the four work products into Clean dataset, SQL analysis and a decision-focused report. Write a README explaining the problem, your assumptions, the decisions you made, tests actually performed and what remains incomplete.
Give a five-minute walkthrough: one minute for the problem, two for the work and evidence, one for trade-offs and one for the next improvement. If you have not implemented a proposed system, label it a design or prototype rather than a deployed solution.
Acceptance: a reviewer can locate each work product, reproduce the key reasoning and identify the limits without a private explanation from you.
The portfolio brief
A fictional training store needs to know which course format has the highest net sales. The source contains refunds and inconsistent labels. Build an analysis whose definitions can be reproduced.
Deliver: Clean dataset, SQL analysis and a decision-focused report.
| format | gross sales | refunds |
|---|---|---|
| Live | 1200 | 150 |
| Recorded | 900 | 50 |
| Workbook | 400 | 20 |
Use these small inputs to make the reasoning visible. They are not a representative dataset, a real client engagement or evidence of production performance. Where the brief requires additional sample records, create them yourself, label them synthetic and explain why you added them.
The ZIP includes the case CSV, four stage worksheets, course sequence, decision log, test log, portfolio README template, review rubric and reference reasoning. It is a starter kit for your work, not a completed application, professional report or proprietary project file.
Check your reasoning
Gross sales are 1200 and refunds 150. What is net sales, and what can it not establish?
Write your answer and assumptions before opening the reference.
Read the reference reasoning
Net sales are 1050. Without costs this does not establish profit; without a comparable period it does not establish growth.
Portfolio review rubric
| Criterion | Points | Evidence required |
|---|---|---|
| Problem and scope | 4 | A clear user, need, boundary and assumptions |
| Role-specific work | 8 | 2 points for each of the four stage acceptance checks |
| Reasoning and validation | 4 | Independent checks, actual results and uncertainty |
| Communication and reproducibility | 4 | A usable README, source links and reviewable work products |
Aim for at least 16/20 as a self-review target, with no missing stage acceptance check. This is a WikiFree practice rubric, not an industry credential or a hiring assessment.
Interview practice
Walk me through one cleaning decision and its effect on the result.
Answer using the case: context, your action, evidence and limitation. Describe this honestly as a self-directed project. Do not present fictional organizations, invented interviews or practice results as paid work experience.
Your progress
Use this checklist as a personal study aid. Progress is stored in this browser when local storage is available; it is not an account record or a certificate.
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Questions before you start
Will this path qualify me for a job?
It helps you study relevant foundations and produce a work sample. Employers may require additional skills, qualifications and experience. Review actual role requirements before applying; no job or certification is guaranteed.
Are all tools and certificates free?
The linked learning routes were selected for free viewing or reading. Follow the separate access and certificate notes on each course. Paid tools and cloud deployment are optional; document a local design when implementation resources are unavailable.
Can I follow this on a phone?
You can read the path and many learning resources on a phone. Coding, detailed spreadsheet work, design tools and mobile-app development are easier or require a suitable computer. The page is designed to reflow; that is not a claim that every physical device has been tested.
Questions & discussion
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