Researchers have found that students learn better and retain more if the students are engaged in activities that require thinking and processing information, rather than passive learning. With increasingly easy access to computers and with several notable statisticians calling for greater computer use in statistics courses, it makes sense for some of these activities to be computer based. Currently, several World Wide Web (WWW) sites provide Java simulations covering statistical topics, which may be used in statistics courses. The present study investigates whether WWW simulations lead to improved understanding of statistical concepts in comparison to hands-on activities and also what effect there is on student attitudes. Introductory statistics students were randomly assigned to either a hands-on lab group or a WWW computer simulation group and completed lab exercises on sampling distributions and confidence intervals. Data was obtained on the students' attitudes, performance on conceptual questions pertaining to the two topics, course performance, and GPA. The students were also surveyed as to their preferred method of completing lab exercises;Participants in the study were 127 introductory statistics students at Iowa State University, during the spring semester of 1999. A comparison of a computer simulation group and a hands-on activity group found no difference in the students' understanding of confidence intervals, understanding of sampling distributions, attitudes towards statistics, attitudes towards mathematics, or attitudes towards computers. One finding that was significant however was that students who were exposed to the use of both the hands-on activities and the World Wide Web computer simulations preferred the simulations;This study indicates that computer simulations are a viable alternative hands-on activities in college level introductory courses. Instructors can use the simulations to add variety to their classrooms while teaching their students these statistical concepts.