This document is an English-language abstract (approximately 1,500 words) of an empirical investigation carried out in an experimental school in Finland called Alppilan Yhteislyseo. The experimental group consisted of 119 pupils whose average age at the end of the experiment was 15.8 years. The experimental period in algebra started in grade 7 and lasted three school years. The pupils were divided into two groups, the one using the traditional textbook by Vaisaia, and the other using the text material developed by Malinen. Retention of material was then measured by tests. Attitudes, ability, and achievement were the factors measured by the tests. The results were factor analyzed for cognitive domain factors and for affective domain factors. In the second phase, the important variables were subjected to further analysis. In the subsequent phase, the relations between dependent variables and intervening variables were studied. The multiple correlation coefficients varied from 0.78 to 0.84 when complex algebra and marks in algebra were predicted in this system. The variables predicted most important were simple algebra and attitude variables. The importance of reasoning ability was slight and that of numerical ability insignificant. Some other results of the experiment are also described. (Author/GDB)