This activity builds on “Least-Squares Lines and Correlation – Was Leonardo Correct?” from Exploring Statistics with Fathom, which examines the accuracy of various ideal ratios between body measurements that Leonardo da Vinci prescribed during the Renaissance. It extends the original activity by asking students to compare different ways of describing relationships and of measuring what is “typical” in a population.

Students will examine the use of Least-Squares lines, mean, median and percentiles to identify typical ratios between different body measurements. This activity also offers the possibility of extending the discussion to sampling, by offering a very large collection (3982 cases) from which samples of different sizes and compositions can be drawn to test for accuracy and bias. This activity assumes some familiarity with interpreting the slope and intercept of a line in context, and provides an entry point to discussing percentiles and distributions, particularly the Normal distribution.