Topic review.

Choose centre and spread for the question; state units and identify grouped estimates.

Order data and state the quartile convention before finding a five-number summary.

Compare box plots on a common scale; IQR describes the central half, not the whole range.

State percentile conventions and interpolation assumptions.

Distinguish population from sample standard deviation and choose the right denominator.

Preserve paired observations; describe direction, strength and form without inventing causation.

Use the conditioning group's total for two-way-table percentages.

Report sampling, measurement and presentation limitations alongside a supported conclusion.