According to the above correlations, GCK is the independent variable
that was most strongly related to geometry proof problem-solving
performance. The other variables—GPS (general problem-solving skills)
and GRS (geometry reasoning skills)—were also significantly correlated
to PTG, but to a lesser degree. This suggested that whilst GCK could be
the major predictor of geometry proof problem-solving performance,
students’ general problem-solving skills (GPS) and their reasoning skills
(GRS) carried significant load in the regression model.