We report on a large-scale implementation of mastery-based grading in a General Education Introductory Statistics course at California State University Los Angeles. In Fall 2018, the course had 80 sections of approximately 30 students each and was taught by 37 instructors who ranged from long-time, experienced instructors to brand new teaching associates. In Spring 2019, the course had 16 sections with eight instructors. We discuss the design of the course, the structure of the assignments, and how we implemented mastery-based grading given that the course instructors are, for the most part, new to mastery-based grading. We have now completed two semesters of implementation and want to share our experiences and the adjustments we made for Spring 2019 as a result.