Divide into groups of 8 to 12 people. For each group member, measure the person’s height and also measure his or her navel height, which is the height from the floor to the navel. Is there a correlation between height and navel height? If so, find the regression equation with height expressed in terms of navel height. According to one theory, the average person’s ratio of height to navel height is the golden ratio: (1 + √5)/2 ≈ 1.6. Does this theory appear to be reasonably accurate?