Statistics

📖 Measures of central tendency & dispersion

Mean, median, and mode summarise a data set with a single representative value, while range, variance, and standard deviation describe how spread out the data is — both are foundational to reading any administrative report with numbers in it.

• Correlation & regression — basics of how two variables move together
• Index numbers — used to track relative change over time (e.g. price indices)
• Sampling methods — random, stratified, systematic sampling basics