Studies such as the Effective Teachers of Numeracy Study (Askew, Brown, Rhodes, Johnson, & Wiliam (1997) have contributed much to our understanding of what constitutes effective teaching of numeracy. This paper aims to build on these findings and to contribute a model that could be used to understand teachers’ numeracy practices and the factors that influence these practices. Through a synthesi...

The Johnson-Neyman (JN) procedure, as originally formulated (Stat Res Mem, 1 (1936) 57-93), applies to a situation in which measurements on 1 dependent (response) variable, X, and 2 independent (predictor) variables, Z1 and Z2, are available for the members of 2 groups. The expected value of X is assumed to be a linear function of Z1 and Z2, but not necessarily the same function for both groups...