Okay, let’s break this down. Mark has a mix of research, psychology, and data analysis skills, which are in demand across various industries. His location in Baltimore, MD, is a plus, but salaries can vary. Considering his skill set and certification, I'd estimate his hourly rate to be around $45, which is a reasonable rate for a professional with these skills in the US. This rate is lower than what professionals with similar skills in high-demand cities like San Francisco or New York might charge, but it's a good starting point for someone in Baltimore.