Informal Inferential Reasoning: Interval Estimates of Parameters

Abstract

This research examined the informal inferential reasoning of senior secondary school students (age 17) when engaged in a computer-simulated sampling activity calling for the estimation of population parameters. The students undertook a task involving interval estimation of parameters within a computer-simulated environment. The research observed the students while they made and then explained their parameter estimates in order to better understand how the students formed the interval estimates, with particular attention to different strategies they adopted in forming these estimates. Activities involved sampling and estimating across three different sample size situations followed by a reflection stage to compare the estimates. Results of the analysis of the discussion between the students and the researcher during the students' activities are presented. A number of strategies for forming an interval estimate emerged. The students experimented with choosing different strategies for forming the interval estimate when a new sample (observed values) was drawn. The research findings are useful for informing the teaching of interval estimation to school-aged students.