Free practice zone
Practise before you enrol — no account needed
Sample questions, Excel challenges, SQL and Python exercises, a KPI interpretation challenge and free introductory lessons.
Sample questions
Data Interpretation
- Reading a chart honestlyBeginner
- Percent vs percentage pointsBeginner
Excel
- Pass or fail flagBeginner
- Copying a formula with a fixed rateBeginner
- Total revenue for one regionBeginner
- Count large ordersBeginner
GIS
- Mapping counts vs ratesIntermediate
- Measuring distance correctlyBeginner
Machine Learning
- Recognising overfittingBeginner
- Checking AI-generated summariesIntermediate
- Spot the data leakageIntermediate
- Metrics for rare outcomesIntermediate
Power BI
- Measure or calculated column?Intermediate
- Leading vs lagging indicatorBeginner
Probability
- Sum of two diceBeginner
- At least one defective itemIntermediate
Python
- Filter a listBeginner
- Average by group in pandasBeginner
- Clean missing valuesBeginner
R
- Mean with missing values in RBeginner
- Read a dplyr pipelineBeginner
SQL
- Regions above a revenue thresholdBeginner
- COUNT(*) vs COUNT(column)Beginner
- Customers with no ordersIntermediate
Statistics
- Interpreting a p-valueIntermediate
- Typical household incomeBeginner
- Correlation and causationBeginner
- What a 95% confidence interval meansIntermediate
Survey Methods
- Summarising a Likert itemBeginner
- Fix the questionnaire itemBeginner
- XLSForm skip logicBeginner
- Why use survey weights?Intermediate
Excel challenges
Type a formula and it is evaluated against the sheet — just like in Excel.
BeginnerSample content
Total actual sales
Return the total of the Actual column (C2:C7).
| A | B | C | D | |
|---|---|---|---|---|
| 1 | Month | Target | Actual | Region |
| 2 | Jan | 500 | 470 | Kigali |
| 3 | Feb | 500 | 530 | Kigali |
| 4 | Mar | 550 | 610 | North |
| 5 | Apr | 550 | 505 | North |
| 6 | May | 600 | 640 | Kigali |
| 7 | Jun | 600 | 590 | South |
This practice tool evaluates a subset of Excel functions (SUM, SUMIF(S), COUNTIF(S), AVERAGEIF(S), IF, AND/OR, ROUND, MIN/MAX, MEDIAN, SUMPRODUCT, INDEX, MATCH, XLOOKUP, VLOOKUP, IFERROR and more).
Coding exercises
- PythonCalculate summary statisticsLoad sales.csv with pandas. Print the number of rows, the total revenue, and the mean units per order rounded to 1 decimal place.Beginner
- PythonRevenue by regionCompute total revenue by region, sorted from highest to lowest, and print the result.Beginner
- PythonClean missing values in a datasetIn survey.csv, print the number of missing values per column. Then fill missing income values with the median income of the respondent's district, and print the missing count again to confirm it is zero.Beginner
- PythonBuild a regression modelFit a simple linear regression of yield_t_ha on fertiliser_kg. Print the slope rounded to 4 decimal places and interpret it in a comment.Intermediate
- PythonAnalyse survey responsesSummarise the 1–5 satisfaction score: print the percentage distribution (excluding missing), then the top-two-box share (scores 4 or 5) as a percentage rounded to 1 decimal.Beginner
- PythonLabour market indicatorsUsing the synthetic labour-force sample, compute the unemployment rate (unemployed ÷ labour force, where the labour force is employed + unemployed) as a percentage rounded to 1 decimal. Then compute it by age_group.Intermediate
- SQLWrite SQL queries to aggregate salesUsing the sales table, return each region with its total revenue as total_revenue, highest first.Beginner
- SQLFind customers without ordersList the customer_id and customer_name of customers who have no rows in sales.Intermediate
- RMedian income by district in RRead survey.csv and compute the median income by district, ignoring missing values. Base R is enough.Beginner
Interpret a report
Dashboards only help if you can interpret them. Study the report, then answer three questions.
Skills programme — monthly KPI report
Synthetic data for practice · Jan–Jun
- Enrolled (Jun)
- 575
- +75 vs target
- Target (Jun)
- 500
- Monthly goal
- Completion rate
- 50%
- -11 pts since Jan
- Lowest district
- 41%
- District C
Free introductory lessons
- Advanced Microsoft Excel for Data AnalysisRelative vs absolute referencesWhy formulas break when copied, and how to fix them.25 min
- Advanced Microsoft Excel for Data AnalysisLookups with XLOOKUP and INDEX/MATCHCombine tables safely, with sensible not-found handling.35 min
- Power BI & Dashboard DevelopmentMeasures vs calculated columnsWhen to use each, and why it matters for performance.30 min
- R Programming for Data AnalyticsYour first R sessionConsole, scripts and projects.25 min
- Python Programming for Data AnalyticsLoading and inspecting dataread_csv, head, info and describe.30 min
- SQL & Database QueryingAggregation with GROUP BYTotals and averages by group.35 min
- Descriptive & Inferential StatisticsMean, median and when they disagreeSkewed data, like income, needs care.25 min
- KoBoToolbox for Digital Data CollectionSkip logic with relevantAsk only the right questions.30 min
- Questionnaire Design & ValidationCommon question-wording errorsLeading, double-barrelled and vague questions.30 min
- Data Science FoundationsTrain/test split and baselinesHow to know if a model is useful.30 min
- ArcGIS Pro EssentialsCoordinate reference systemsWhy your layers don't line up.30 min