This article describes a study of learning when students used interactive spreadsheet-based computer tutorials in a mathematical literacy course. It foregrounds theories relating to the role of computer technology (and specifically spreadsheets) as a mediator for learning of mathematics. It outlines the application of quantitative methods involving pre- and post-testing of students, both in the computer laboratory and in the lecture sessions, and discusses factors constraining the experimental design and the usefulness of the results. There are indications that the data reveal real differences between the learning experiences in the lecture sessions and the computer laboratories. It appears that in some respects the computer tutorials were more effective in conveying the concepts than the lecture sessions were. A method of analysing and representing the data, that tracks the extent of learning of concepts through the pre- and post-tests, was developed. It allows for the performance of sub-groups of students to be examined separately. This analysis shows that simple definitions of disadvantage (such as having English as a second language) are inadequate to account for the poor performance of students in the lower quartile.