The assessments included seven tasks investigating students’ understandings, processes and skills in the area of statistics. Statistics is concerned with the collection, organisation and analysis of data, and the estimation of probabilities and use of probabilities for prediction.

Three tasks are trend tasks, with data for 2005 as well as 2001. Four tasks are link tasks (to be used again in 2009, so only partially described here). Two of the trend tasks were identical for year 4 and year 8. One of the trend tasks was administered for year 8 only.

The two tasks administered for both year 4 and year 8 showed substantial growth over those years. On average, there was a 36 percent increase in performance on tasks from year 4 to year 8. There was also a small improvement from 2001 to 2005 in year 4 (an average of 2.2 percent) and a moderate improvement between 2001 and 2005 in year 8 (average of 5.4 percent). In year 8, the tasks involving probability and combinations showed gains from 2001 to 2005, but the task involving computing averages did not.