Collaborating on assignments
I encourage you to collaborate on assignments, as long as the submitted writing is your own, and you ultimately ran all analyses yourself. Solutions to previous years' assignments are off limits!
If you are quoting others' work, put it in quotes! If you are directly quoting, or building on others' writing, provide a citation. See the Rackham Graduate policy on Academic and Professional Integrity for the definition of plagiarism, and associated consequences.