Body fat and body shape

Use this diagram to explain the structure of a data matrix:

Click any of the icons representing the individuals to select his row in the data matrix. Click on the parts of the diagram on the top right to select the column the corresponding columns of the data matrix.

Explain that most data sets can be expressed in a data matrix of this form.

Percentage body fat of individuals is an important measure of their health. In order to determine how body fat is related to other physical characteristics, scientists accurately determined body fat (using an underwater weighing technique) and several other body measurements from a group of 252 men.

The diagram shows some of these measurements for the first 50 subjects in the study. (Note that the heights were recorded in inches, whereas the chest and other body circumference measurements were recorded in centimeters!)