As part of the recent history of the mathematics curriculum, reasoning and argument have been emphasized throughout mathematics curriculum standards. Specifically, as part of the Common Core State Standards for Mathematics, the Standards for Mathematical Practice were presented, which included the expectation that students develop arguments and carefully consider others' arguments. Due to its emphasis on reasoning and argument, argumentation is one possible way students can meet the expectations of these standards. However, when used in mathematics, argumentation is commonly limited to proofs. Therefore, the use of argumentation in mathematics in ways apart from proofs is needed. Through an examination of students in a college-level introductory statistics classroom, this study examined how engaging in the statistical problem-solving process served as an avenue for developing students' understanding of argumentation. This study was a holistic multiple case study with three cases. This study utilized data in the form of lesson documents, writing prompts, interviews, field notes, observation video, and the researcher. The data were analyzed and coded using Creswell's five general steps for analyzing qualitative data, Toulmin's Model of Argument, and levels of understanding of argumentation, which emerged from the data. Results from this study indicated that through participating in argumentation training and engaging in the statistical problem-solving process, the participants displayed an increased understanding of argumentation. However, participants did not provide evidence of reaching a deep level of understanding of argumentation. Participants' tendencies to limit their engagement in and recognition of the argumentation process to the statistical problem-solving process led the researcher to question the role of authority in the classroom and its potential influence on the argumentation process. The findings from this study suggest a need for future research examining processes for developing a deeper understanding of argumentation in students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]