Should a group consist of only undergraduates or graduate students, since there are different requirements for 686 students? If a group does contain students from both 486 and 686, then how does it deal with the differing requirements?

Generally we would like each group to represent the STAT 486/686 enrollment. In unique cases with a very strong UG, they may participate in a graduate class group; the grading will be adjusted for their being enrolled in STAT 486.