Data Analysis
Correlation, time series, index numbers and standardisation.
15 topics
Data Analysis covers scatter diagrams and correlation, lines of best fit, interpolation and extrapolation, correlation and causation, Spearman's rank at Higher tier, time series, moving averages, index numbers and standardised scores.
Correlation and causation is the most reliably examined idea in the unit, and answers need a plausible confounding variable rather than a general statement that one does not imply the other. Interpolation and extrapolation questions expect you to identify which you are doing and comment on reliability. Time series work rewards separating the trend from seasonal variation, and moving averages must match the cycle length to work at all. Index numbers are simpler than they look — subtract one hundred to read the percentage change — but require care over which value is the base.