Students classify variables as categorical, discrete numerical, or continuous numerical, calculate mean, median, mode, range, and interquartile range from raw data or simple frequency tables, and construct and interpret box plots using five-number summaries to compare centre, spread, skewness, and possible outliers. They construct and interpret histograms with appropriately scaled contiguous intervals, describe distributions by centre, spread, clusters, gaps, skewness, and possible outliers, and use scatterplots and lines of best fit to describe linear correlation and make cautious predictions, distinguishing association from causation and interpolation from extrapolation. They evaluate random, stratified, systematic, convenience, and voluntary-response sampling for undercoverage, nonresponse, self-selection, and other bias, distinguishing systematic bias from random sampling variation when generalizing from samples to populations.