TLF ID M009163
This is a 26-page guide for teachers. In year 8, students developed an understanding of the nature of censuses, surveys and observational studies. Year 9 develops this understanding further, and introduces examples of experimental investigations with an emphasis on random allocation of the combinations of experimental conditions. Experiments provide a natural context for comparisons of continuous data across categories of categorical variables, and these comparisons are the focus of year 9.