Classify data as categorical or numerical and as discrete or continuous, select appropriate censuses, surveys, observations, or experiments, and evaluate samples and survey questions for representativeness and bias. Calculate and interpret mean, median, mode, and range, explain how outliers affect measures of center, construct and interpret histograms, and identify misleading scales, intervals, labels, and visual features in data displays. Construct scatter plots of paired numerical data and describe positive, negative, or nonexistent associations, including linear or nonlinear patterns, clusters, gaps, and outliers, without inferring causation or using regression or correlation coefficients.