So close

I am currently editing my SOP. In the last few days I have found new excitement for my project as I am only an edit of my SOP away from starting.

In the process of creating a Standard Operation of Procedure document I am puzzled on one section. In my experimental design music is played for 30 minutes and then the last heart rate and saliva samples are taken. The question is how do I know that 30 minutes is long enough?

Also in this process I have decided to only use one sex in my pool of participants. I have made this decision based on how many tests I can perform. My decision on which sex to study will be based on research on which sex is more prone to high anxiety in adolescence. According to my pulmonary research, females are more prone, so most likely my study will just be conducted on females.