+1 to the confused question What are we trying to test? That isn't clear so it's impossible to actually know how to follow up. In this case "did not respond"

+1 to the confused question What are we trying to test? That isn't clear so it's impossible to actually know how to follow up. In this case "did not respond" could be perfectly sufficient, but we couldn't possibly know because all we know is: "The questionnaire included topics on student life, academics, and athletics."