I give my classes a set of survey questions to complete. One question pertains to desired number of hours of sleep per night. In Class 1 I have 38 students, in Class 2 I have 37 students, and in Class 3 I have 40 students. I decide to run two different analyses: 1. I wish to compare the means Class 1 to Class 2 - Do these classes differ in their sleep habits? 2. I wish to see if all of my students together have mean sleep habits that differ from the national average for college students' desired sleep length. For the statistical tests that I perform, the df for study 1 is ______, the df for study 2 is ______