Students from five high schools participated in a 2 to 4-week microcomputer based laboratory (MBL) physics curriculum in two groups. One group completed the curriculum entirely online, and the other completed the same curriculum in a traditional classroom setting. Variables were collected to predict student success on a post-unit measure of physics ability through correlations. Traditional, literature-suggested, variables such as math ability, physics aptitude, and demographic information were combined with variables related to the mode of delivery of instruction. Several computer-related variables, such as students' access to a computer at home and how often students accessed the Internet were included in the models. Math ability and physics aptitude dominated the models regardless of the method of delivery of instruction. Computer-related variables were included in the model for the online group; however, they were not significant. (Contains 3 figures and 6 tables.)